While private eye Karim Washington scours San Francisco for a missing teen who was involved in a cryptic game, OA wakes up in unfamiliar surroundings.
At the clinic, OA discovers what happened to her friends back at Hap's; Karim turns his attention to a doctor who worked for Pierre Ruskin.
In Michigan, Steve begs the gang to try jumping to another dimension, and a presence in Buck's mirror inspires an unlikely pilgrimage.
Karim visits Nina at the clinic for help finding the secret entrance to the house; Hap meets a fellow traveler, and Homer goes on a date.
After a harrowing ordeal, OA and Karim find themselves locked inside a labyrinth of puzzles; nagging doubts prompt Homer to snoop on Dr. Percy.
As BBA and the kids head west, an alarming news report forces them to speed up their plans; Jesse wrestles with lingering trauma from the shooting.
Karim returns to the house with reinforcements, OA tries to access Nina's memories, and Hap offers to discharge Scott -- after one last experiment.
While BBA and the others converge on the clinic, Nina persuades Hap to show her his research, and Karim unlocks one of the house's final secrets.