[s4e20] The Slaughterhouse | 90% Essential |

: A comedic side-plot involves Captain Holt losing Amy Santiago's favorite fountain pen while his own is being repaired in Germany.

Jake Peralta and Rosa Diaz compete to join a prestigious task force called , led by their idol, Lieutenant Melanie Hawkins (guest star Gina Gershon ). [S4E20] The Slaughterhouse

: Despite promising not to compete, both detectives sabotage each other to impress Hawkins while pursuing a bank robber named Billy Ocampo. : A comedic side-plot involves Captain Holt losing

: The episode sets up a major series arc when it is revealed that Hawkins is actually a dirty cop who is robbing the banks herself. Subplots & Comedy led by their idol