Facing writer’s block and still unable to properly deal with Beckett (Stana Katic) now that he knows she lied about hearing him confess his love, Castle (Nathan Fillion) jumps at the opportunity to shadow the gang unit’s unorthodox Detective Slaughter (Firefly co-star Adam Baldwin)… until he learns the detective’s last three partners have all died in the line of duty and just how many laws Slaughter will bend to get his man.
Even though she’s temporarily sidelined preparing with Esposito (Jon Huertas) and Ryan (Seamus Dever) for an upcoming trial, Beckett finds herself back on Dr. Burke’s (Michael Dorn) couch feeling betrayed by Castle working with another cop and wondering why her partner is acting like a “complete jackass.”
Slaughter and Castle’s instigation into the gangbanger leads to turning up that not one, but two other gangs wanted the man dead, but to figure out why they must figure out why he died they must first discover why their victim dug up the heads of three members of a rival gang.
The trail leads to a dangerous Mexican gangster (Reynaldo Gallegos) who Slaughter believes they can take down themselves but almost gets both of them killed. When he goes even further by pressuring a young kid into giving false testimony to put away the gangster he wants for the crime it’s too much for Castle who goes back to Beckett for her help in finding the real killer.
In the episode’s B-story Alexis (Molly C. Quinn) balances her joy at getting accepting into Stanford against her original rejection letter, which leads to some fatherly advice about deciding whether you want something enough to get over the hurt. Although we don’t get much of Castle and Beckett together in this episode (except the final ten minutes) it was fun to see Fillion and Baldwin reunited, especially with a role for Baldwin that he might be able to reprise for another guest-spot.