Plot

When a coded document hidden by a murdered bail bondsman gets Castle's imagination running wild, Beckett must steer the case back to the violent felons who populated their victim's world - only to discover that maybe Castle's crazy theories aren't so crazy after all. Complicating matters is the surprise arrival of Beckett's ex-partner (now a bounty hunter). As the two reunite over a history that Castle has no part of, Castle is forced to watch the relationship take a turn towards the romantic.—ABC Publicity

Bail bondsman Deon Carver is found with his skull smashed with a sharpshooter cup in his office. Interference on a walkie-talkie leads to the discovery of a bug that was planted in his office. Another strange finding is the killer appears to have called 911 after searching the office for an hour. While searching the body at the morgue, Lanie finds a piece of paper hidden in his Deon's sock with apparently random lines drawn on it. Castle and Becket investigate Deon's criminal clientele, starting with repeat-offender Random Pierce. But when Random runs, he is captured by bounty hunter Mike Royce, formerly Becket's training officer after she graduated the Police Academy. They soon find out it all relates to missing gems from a previous robbery, which several other suspects could be after, including priest Arron Roe, Carver's widow and some ex-cons.—KGF Vissers