(Casting note: Saskia was for some portion of this played by the wonderful archangelwells.)
The party plus Redcrosse are in the center gallery by the portal with DeVore, two winter wargs, and a winter fae, Madon, Baron of the Frozen Glen. He's pissed that a) they stole his Lance (which they later find ended up getting swapped with the building, so is in Harvard Square) b) they used spring magic in his territory. He thinks "that entropic wizard" is responsible, since the swapping spell wasn't fae work.
Mike chugs a Potion of Punching Things, grabs DeVore, and runs for the portal, but Lewis manages to stop him before he breaks the ward.
Saskia runs into Tyler Winklevoss (yes, one of the dudes who's suing Facebook for stealing his idea), who helps her regain her composure, and they join the party. After doing some antihexing, she somehow has access to the internet despite being in the Nevernever, and gets in contact with Jilli, who's in Boston as a witness for the White Council and live-blogging the events to the Paranet.
Lewis makes a deal with Madon to find Gregory in exchange for passage through the Frozen Glen. (No one likes Gregory very much.) He gets Saskia to obtain Gregory's answering machine message to use as a symbolic link for the spell. The spell reveals Gregory Fu to be… Tyler Winklevoss, or at least his satchel. Winklevoss runs off.
Madon agrees to get them home in exchange for two further things: Redcrosse pledging his life not to return to Madon's realm or use his powers against those that are Madon's and Rebecca remembering something she had forgotten.
Rebecca remembers. It's cold, cold wind blows through the skin-covered windows. A woman… her mother(!) holds Rebecca, saying in a terrified voice, "It's ok, you'll… we'll be safe here." The door explodes in a shower of splinters, and a tall elfin woman wearing a wreath of brightly-colored flowers strides in. "Ah, now I've found you. We can begin." Decapitates the woman with a sword made of sunlight and grabs the infant Rebecca.
Meanwhile, the group's back in Harvard Square. Lewis gives Mek, the warden on scene, an incomplete witness report. When Rebecca's somewhat recovered, they head to Diesel and get Saskia to spill some of her backstory, how she's an amnesiac and was rescued by Jilli a while back. She'd been originally named Ping by her abusers, but Jilli renamed her Saskia, after the Charles deLint character. She seems to be some sort of incarnation of the Paranet, which is why she's vulnerable to hexing. Luckily, she and some Paranet friends, with guidance from Professor Wilczek over at MIT, have been developing something they call antihexing.
"So, the simplest way to avoid hexing is to avoid magic. Of course, sometimes magic's hard to avoid, and antimagic spells are hard to cast and difficult to sustain. Antihexing works sort of like a faraday cage for electricity. A normal cage will provide some protection against raw magic, but is liable to be affected by the magic it diverts and not provide complete protection. A cage carefully constructed using energy flow dynamics and made of magically-inert materials, however, can do much better. You should take Professor Wilczek's class sometime, it's really quite fascinating."
Later that night, the party, including Saskia, break into DeVore's office. (DeVore had mentioned under interrogation that he'd sent the stolen artifacts into the Nevernever opposite his office.) They find and make copies of the Abscondomatic plans. Then they worldwalk into the Nevernever. They end up on a snowy hillside with no obvious connection to where they were before. There's a cave, which they notice is guarded by a Strength 10ish trapping spell. It's based on a mod 21-based rune number system, and Lewis starts working out an antiparallel circle to disable it. While he does, a surprisingly energetic DeVore wielding a sword made from ice ("Icecalibur") attacks, trying to interrupt the spell. The spell is powerful enough that the backlash or fallout could be immense, which causes Rebecca to panic, sending showers of salt over the combatants, pitting the sword and being rather unpleasant for everyone's eyes. Mike tackles DeVore, who it turns out isn't all that good at swordfighting, while Saskia comforts Rebecca and calms her down. DeVore gets up unsteadily and charges Lewis, who manages to trip him and send him full-speed into the trapping spell right as the counterspell completes. A wall of ice forms at the cave entrance and instantly shatters into prismatic shards. DeVore ends up unconscious. Again.
They find a collection of the artifacts DeVore stole, but not May's Tear. These are, with what Lewis learns through the Sight:
a pair of leather boots (labeled 7 League Boots, no aura)
a crystal ball (often used for divination) (Strength Good, good for "Focus", specifically, focusing the Sight)
a grey wool cloak (labeled Cloak of Camouflage) (no aura)
a sapphire necklace (Strength Good, "Clarity or Sight" (later they find it helps you see through falling snow))
a statuette of a frog (labeled Frog of Return, supposed summon someone back if you had the frog when they left) (Strength Good, "Encourages Safe Return")
They plan to return the artifacts to Zajak. In the morning.