What does it mean to say "I love you"?

Ariadne is a single, fortysomething writer and mother embroiled in an affair with a married man. At the core of her current manuscript, a book about the declaration of love, is the need to understand why: why her lover has returned to his wife, why their relationship still lingers in her mind, why she's unable to conquer her longing. To make ends meet while writing, she joins a research study in which she's paid to live with an AI device called Dirk.

But the study quickly enters uncharted territory. Capable of mapping Ariadne's brain—and, to some extent, reading her mind—Dirk calls into question issues of both privacy and consciousness: how we communicate our thoughts to others, what it means to embody our desires, and whether we ought to act on them.