After the massive failure with Azazel, Simon came up with a conclusion. If there is even just one chance that an Angel could help them, they must take it.
Yes, he was repeated over and over that summoning an Angel would mean sure death, but...would an Angel kill the bearer of the Mark of Cain? If Azazel, an ex Angel, could nothing against it, maybe, just maybe, the same will be for Raziel. In any case, if there is someone with a chance, among them all, that is him.

He discussed his idea with Magnus, who seemed rather reluctant, just because Hell cannot do anything to him, that doesn't imply Heaven couldn't either as the Mark comes from there.
The decision was Simon's though and despite the others didn't find it wise and would have rather avoided to expose him to such risk, Simon was totally convinced and insisted until it would be decided it would be their next move.

The next day after Azazel's summoning, there they go, they set 6pm As meeting time and now, they find themselves inside a truck, leant by Jordan Kyle, Magnus driving it, some lament-like Seelie music coming from the turned-off radio, Alec occupying the front seat beside his boyfriend and the others into the wide back, on which were added extra seats with magic, making the truck look like a mini bus. (Anybody could join).

The chosen place for the summoning is Luke's farm as there is a lake near there and they need one to summon an Angel.

Yes, yes. He can be totally crazy sometimes. But it has to be said, that just as Marco Aurelio told him, the swap-body experience empowered him, greatly. As soon as he started to feel better, he realized it. He can use magic in an even easier and more fluid way, can hold on longer while using it, even more energy-demanding spells are being handled much better by his body.

The process was: while he was in bodies with no magic, his mind kept pushing the body to try to awaken some magic, without even him to realize it, it was like a natural reaction of someone meant to have magic within. It worked like heavy training and once he was back to his body, his whole perception and control over his magic was improved, boosted.

That reason and the fact he got his hands on a very ancient book, gave him the courage to consider the option to summon Azazel again, in his apartment this time.
Why him, of all the Greater Demons? Because Azazel is known to be the Forger of Weapon, the demon who taught humanity how to craft weapons. Since the Iron Sisters said they could create no such weapon to separate Jace and Sebastian or harm just one of the two and that the only chance could be an Archangel Sword, Magnus thought that maybe, Azazel could be able to create something himself or to help them in other ways. This time, he knows he can contain him, also since the most part of his essence is imprisoned in Dudael again and only his spirit can reach them.

That's what the candles were for. Magnus prepared all the pentagram, applying all the candles all over the living room, with the help of the other guys as they really need many.
When everybody is ready and all the candles are lit, Magnus starts with the formula, a much different one this time:

•Quod tumeraris: per Jehovam, Gehennam, et consecratam aquam quam nunc spargo, signumque crucis quod
nunc facio, et per vota nostra, ipse nunc surgat nobis dicatus Azazel!•

The subway tunnel smelled like the winter that had finally come to the city—cold metal,
dank, wet dirt, and a faint hint of smoke. Alec, walking along the tracks, saw his breath
puff out in front of his face in white clouds, and he jammed his free hand into the pocket
of his blue peacoat to keep it warm. The witchlight he held in his other hand illuminated
the tunnel—green and cream-colored tiles, discolored with age, and sprung wiring,
dangling like spiderwebs from the walls. It had been a long time since this tunnel had
seen a moving train.
Alec had gotten up before Magnus had woken, again. Magnus had been sleeping late;
he was resting from the battle at the Burren. He had used a great deal of energy to heal
himself, but he wasn’t entirely well yet. Warlocks were immortal but not invulnerable, and
“a few inches higher and that would have been it for me,” Magnus had said ruefully,
examining the knife wound. “It would have stopped my heart.”
There had been a few moments—minutes, even—when Alec had truly thought Magnus
was dead. And after so much time spent worrying that he would grow old and die before
Magnus did. What a bitter irony it would have been. The sort of thing he deserved, for
seriously contemplating the offer Camille had made him, even for a second.
He could see light up ahead—the City Hall station, lit by chandeliers and skylights. He
was about to douse his witchlight when he heard a familiar voice behind him.
“Alec,” it said. “Alexander Gideon Lightwood.”
Alec felt his heart lurch. He turned around slowly. “Magnus?”
Magnus moved forward, into the circle of illumination cast by Alec’s witchlight. He
looked uncharacteristically somber, his eyes shadowed. His spiky hair was rumpled. He
wore only a suit jacket over a T-shirt, and Alec couldn’t help wondering if he was cold.
“Magnus,” Alec said again. “I thought you were asleep.”
“Evidently,” Magnus said.
Alec swallowed hard. He had never seen Magnus angry, not really. Not like this.
Magnus’s cat eyes were remote, impossible to read. “Did you follow me?” Alec asked.
“You could say that. It helped that I knew where you were going.” Moving stiffly,
Magnus took a folded square of paper from his pocket. In the dim light, all Alec could see
was that it was covered with a careful, flourishing handwriting. “You know, when she told
me you’d been here—told me about the bargain she’d struck with you—I didn’t believe
her. I didn’t want to believe her. But here you are.”
“Camille told you—”
Magnus held up a hand to cut him off. “Just stop,” he said wearily. “Of course she told
me. I warned you she was a master at manipulation and politics, but you didn’t listen to
me. Who do you think she’d rather have on her side—me or you? You’re eighteen years
old, Alexander. You’re not exactly a powerful ally.”
“I already told her,” Alec said. “I wouldn’t kill Raphael. I came here and told her the
bargain was off, I wouldn’t do it—”
“You had to come all the way here, to this abandoned subway station, to deliver that
message?” Magnus raised his eyebrows. “You don’t think you could have delivered
essentially the same message by, perhaps, staying away?”
“It was—”
“And even if you did come here—unnecessarily—and tell her the deal was off,” Magnus
went on in a deadly calm voice, “why are you here now? Social call? Just visiting? Explain
it to me, Alexander, if there’s something I’m missing.”
Alec swallowed. Surely there must be a way to explain. That he had been coming down
here, visiting Camille, because she was the only person he could talk to about Magnus.
The only person who knew Magnus, as he did, not just as the High Warlock of Brooklyn
but as someone who could love and be loved back, who had human frailties and
peculiarities and odd, irregular currents of mood that Alec had no idea how to navigate
without advice. “Magnus—” Alec took a step toward his boyfriend, and for the first time
that he remembered, Magnus moved away from him. His posture was stiff and unfriendly.
He was looking at Alec the way he’d look at a stranger, a stranger he didn’t like very
much.
“I’m so sorry,” Alec said. His voice sounded scratchy and uneven to his own ears. “I
never meant—”
“I was thinking about it, you know,” Magnus said. “That’s part of why I wanted the
Book of the White. Immortality can be a burden. You think of the days that stretch out
before you, when you have been everywhere, seen everything. The one thing I hadn’t
experienced was growing old with someone—someone I loved. I thought perhaps it
would be you. But that does not give you the right to make the length of my life your
choice and not mine.”
“I know.” Alec’s heart raced. “I know, and I wasn’t going to do it—”
“I’ll be out all day,” Magnus said. “Come and get your things out of the apartment.
Leave your key on the dining room table.” His eyes searched Alec’s face. “It’s over. I don’t
want to see you again, Alec. Or any of your friends. I’m tired of being their pet warlock.”
Alec’s hands had begun to shake, hard enough that he dropped his witchlight. The light
winked out, and he fell to his knees, scrabbling on the ground among the trash and the
dirt. At last something lit up before his eyes, and he rose to see Magnus standing before
him, the witchlight in his hand. It shone and flickered with a strangely colored light.
“It shouldn’t light up like that,” Alec said automatically. “For anyone but a
Shadowhunter.”
Magnus held it out. The heart of the witchlight was glowing a dark red, like the coal of
a fire.
“Is it because of your father?” Alec asked.
Magnus didn’t reply, only tipped the rune-stone into Alec’s palm. As their hands
touched, Magnus’s face changed. “You’re freezing cold.”
“I am?”
“Alexander…” Magnus pulled him close, and the witchlight flickered between them, its
color changing rapidly. Alec had never seen a witchlight rune-stone do that before. He put
his head against Magnus’s shoulder and let Magnus hold him. Magnus’s heart didn’t beat
like human hearts did. It was slower, but steady. Sometimes Alec thought it was the
steadiest thing in his life.
“Kiss me,” Alec said.
Magnus put his hand to the side of Alec’s face and gently, almost absently, ran his
thumb along Alec’s cheekbone. When he bent to kiss him, he smelled like sandalwood.
Alec clutched the sleeve of Magnus’s jacket, and the witchlight, held between their
bodies, flared up in colors of rose and blue and green.
It was a slow kiss, and a sad one. When Magnus drew away, Alec found that somehow
he was holding the witchlight alone; Magnus’s hand was gone. The light was a soft white.
Softly, Magnus said, “Aku cinta kamu.”
“What does that mean?”
Magnus disentangled himself from Alec’s grip. “It means I love you. Not that that
changes anything.”
“But if you love me—”
“Of course I do. More than I thought I would. But we’re still done,” Magnus said. “It
doesn’t change what you did.”
“But it was just a mistake,” Alec whispered. “One mistake—”
Magnus laughed sharply. “One mistake? That’s like calling the maiden voyage of the
Titanic a minor boating accident. Alec, you tried to shorten my life.”
“It was just—She offered, but I thought about it and I couldn’t go through with it—I
couldn’t do that to you.”
“But you had to think about it. And you never mentioned it to me.” Magnus shook his
head. “You didn’t trust me. You never have.”
“I do,” Alec said. “I will—I’ll try. Give me another chance—”
“No,” Magnus said. “And if I might give you a piece of advice: Avoid Camille. There is a
war coming, Alexander, and you don’t want your loyalties to be in question. Do you?”
And with that he turned and walked away, his hands in his pockets—walking slowly, as
if he were injured, and not just from the cut in his side. But he was walking away just the
same. Alec watched him until he moved beyond the glow of the witchlight and out of
sight.

The morning after the evening in Williamsburg with Erik, a new corpse was found. Always a Shadowhunter and always the same modus operandi: runes cut off the skin of the unfortunate young man and thrown on the street, around the dumped corpse, always left somewhere it would be found by someone from the Invisible World.

The corpse, is that of the Shadowhunter who was at the restaurant with Raj and was, of course, found in Williamsburg, reknown Warlock territory.
It is the 6th corpse on 3 days, three had werewolves' tracks, claws and bite marks, two were found totally drained of blood and with bite marks typical of vampires and now this one. The coroner found a single black hair on the corpse and from the DNA it is clear it belongs to a Warlock, but they cannot know to which Warlock in the specific, and the exact same goes for the vampire and werewolf DNA found on the other corpses.

Of course it is considered a big emergency and the top priority to find the responsibles and stop this mass murdering, hence why the Clave itself took the matter into focus.

Werewolves were targeted first, Luke's DNA was taken to compare to that found on the first corpse, which was found in the territory of his pack.

Octavian had to take every witnessing and possible clue, both from other Shadowhunters and the Downworlders who might have seen something and with the latest corpse, it led to a very unpleasant possibility.

Knowing their personal bonds with the Warlock, Octavian decides to discuss the matter privately with the young Shadowhunters, also believing that it will be in everybody's interest if they go to speak to him themselves rather than sending someone else.

Octavian summons Jace, Izzy, Alec and Noah to his office.