Castle is returning Gerald McRaney to his Simon & Simon roots, tapping the acting vet to join Season 8 as the grandaddy of all private eyes.
TVLine has learned exclusively that McRaney is set to appear in multiple episodes as Mason Wood, the head of a legendary and secretive private detective society.
It’s not clear how McRaney’s mysterious character figures into the ABC drama’s larger mythology (if at all), but he’ll first turn up in this season’s 14th episode — the Los Angeles-set outing that will also feature guest star Summer Glau.
McRaney recently co-starred in TNT’s short-lived Sharon Stone drama Agent X.
Castle resumes its current eighth season on Monday, Feb. 1.