ABC’s Castle got a more abrupt ending than cast and crew were necessarily expecting, but Brooklyn Nine-Nine may give Nathan Fillion a little closure. The former Firefly star will guest star on the cop comedy’s fourth season in a role that should sound familiar to Richard Castle readers.

Per Entertainment Weekly, Fillion will appear this coming April in the Brooklyn Nine-Nine role of Mark Devereaux, star of a Law & Order-type series star who offers to aid Jake (Andy Samberg) and Rosa (Stephanie Beatriz) when a crime occurs on his set. Devereaux naturally seeks to call upon his fake-detective experience, just as Fillion’s Castle character tagged along on so many cases for his literary insight.

The April guest spot will also mark Ally McBeal alum Greg Germann’s return to the network, playing producer to Fillion’s Serve & Protect series. For his part, Brooklyn Nine-Nine marks the latest in a number of post-Castle sitcom cameos for Fillion, including Modern Family and this past weekend’s Santa Clarita Diet.

Brooklyn Nine-Nine won’t resume Season 4 until April 11, with Fillion’s episode scheduled sometime in the spring, so stay tuned for the latest on Season 4 in the meantime.