A young girl named Rachel awakens at the bottom basement level of a closed-up building. She's lost her memories and has no idea why she's here.

Zach confronts Rachel after learning the secrets of her past.

Zack and Rachel have found the stairway leading to the building's exit. At last, the end of their ordeal is in sight... but as they're climbing the stairs, suddenly an alarm sounds.

Zack struggles to get Rachel outside the building. But what kind of future awaits her on the outside?