Tova Sullivan, coping with her son's disappearance from thirty years ago, forms a meaningful bond with Marcellus, an octopus at the aquarium she cleans. Their unique relationship becomes a source of comfort and helps Tova face her grief.

The story weaves together two mysteries: a stolen object from the aquarium and the disappearance of Tova's son. Through Marcellus's observations and Tova's investigation, these mysteries gradually unfold and reveal unexpected connections.

The novel demonstrates the resilience of the human spirit, showing how characters find new paths to happiness even in their later years. It emphasizes that it's never too late to discover love, purpose, and belonging.