When the new season begins, Castle is wrestling with how to repair his relationship with Beckett, while struggling to finish his soon-to-be-published bestseller, Heat Wave. But circumstances force the pair back together to investigate the mysterious murder of a man found dead, tangled in the limbs of a tree.

Nothing is as it seems when Castle and Beckett investigate what appears to be the assassination of an intelligence operative. Meanwhile, Beckett's romance with Demming threatens her relationship with Castle, forcing them to confront their feelings for each other.

When a champion swimmer and Olympic hopeful is found dead in a training pool, Castle & Beckett dive in to investigate his murder, and uncover myriad secrets that might have led to his death.

A death in the woods draws Castle back to a terrifying and defining event in his childhood. Investigation leads to obsession, as he attempts to unearth answers that have eluded him for decades, all while Beckett faces a crossroads of her own.