"Caskett" Photo Gallery

Becoming "Caskett"

Castle tells Beckett they need a cool couple nickname and suggests "Caskett." But as they get used to their new relationship, they know they can't get too comfy together. Their partnership will surely be terminated if the NYPD finds out they're together. In "Murder, He Wrote," Ryan accidentally discovers their secret but doesn't tell anyone -- even his best friend and partner, Esposito.