The plot follows Alice (Heather Graham), a young woman living a comfortable but predictable life in London. Her world is turned upside down when she locks eyes with a mysterious stranger, Adam (Joseph Fiennes), while crossing the street. This chance encounter sparks an intense, whirlwind romance that leads Alice to abandon her steady boyfriend and marry Adam almost immediately.

The film follows Alice (Heather Graham), a London-based scientist who abandons her stable life for a whirlwind, intense affair with a mysterious mountaineer, Adam (Joseph Fiennes). As she falls deeper into their obsessive relationship, she begins to uncover dark secrets about his past, leading her to wonder if she truly knows the man she has married.