A woman missing for seven years turns up at a hospital with strange scars on her back but can't -- or won't -- reveal where she's been.

The OA retraces the dramatic twists and turns in her life after a childhood accident, leading up to a fateful encounter far from home many years later.

An agonizing dilemma gives OA a new perspective on the group's plight. Homer resolves to find out what Hap's experiments are really about.

While Hap zeroes in on a new test subject in Cuba, Homer and OA work to perfect their escape plan. Scott reaches his breaking point.

As the group continues its search for the final movement, a startling turn of events gives Hap's work a new urgency.

An ominous new dream and a tense outing with Nancy and Abel take a toll on OA. Steve finds his life in turmoil once again.

After OA recounts a dramatic final night at Hap's, the others begin to see her story in a new light. The fragments of the dream click into place.