Grace Winslow and Professor Catherine Harrow don't know each other. Not yet. Grace is a guarded freshman trying to outrun her mother's legacy. Catherine is a sharp, cold psychology professor who teaches a course called Psychology of Human Intimacy. After their first class, something shifts. Something quiet. Something dangerous. When a family connection is unexpectedly revealed-through a woman they've both learned to love and resent-boundaries begin to blur. What begins in silence becomes obsession. Attachment Theory is a sapphic, slow-burn academic romance about intimacy, power, longing, and everything we pretend not to feel.