The investigation into the death of Beckett's mother once again takes center stage in the January 24 new episode of Castle.  Oh yeah, and, Beckett and Castle will be "taking their partnership to the next level".  Below is a sneak peek for the upcoming episode.

You can also view a promo and photos we previously posted.  Castle fans will NOT want to miss this seminal episode!

Old wounds are reopened when the retired lead detective on Beckett's mother's homicide case contacts her with new information, but then is gunned down right in front of Beckett before he can tell her what he knows. The investigation into his death leads back to a decades-old conspiracy that may hold the answer to who was behind Beckett's mother murder and why. With the stakes and emotions running high, Castle and Beckett take their partnership to the next level, on "Castle," MONDAY, JANUARY 24 (10:01-11:00 p.m. ET). Max Martini guest stars. (ABC/ADAM TAYLOR) NATHAN FILLION, STANA KATIC