The mid-season finale for "Castle" season 8 saw Castle (Nathan Fillion) and Beckett (Stana Katic) finally get back together after eight episodes of nearly breaking up and going their separate ways. The first case the reconciled duo will face when the season returns for episode 9, "Tone Death," involves "High School Musical" alum Corbin Bleu. 

According to a report from Entertainment Weekly, Beckett and Castle will further push their personal and professional relationship back together as they work on a case involving the murder of an acapella singer. Bleu will be portraying Hunter Washington, the leader of a rival acapella and is most likely going to be the primary suspect in the case.

No further details have been released thus far, although it is very likely that the episode won't just focus on the murder case at hand. The episode is most likely going to touch on the re-forged relationship between Castle and Beckett and may even touch upon the short time that has passed between the mid-season finale and "Tone Death."

The very short promotional teaser trailer also shows Castle performing with the acapella group, although it is uncertain at this point what purpose this has in the investigation. Castle and Beckett are also shown investigating at night, flashlights on hand, through what may be an abandoned building, railroad or subway.

As pointed out in a report from Cartermatt the episode has also been pushed back. "Tone Death" was originally meant to launch on Jan. 4 but instead has been delayed for almost a month and is now scheduled to air on Feb. 1 2016. 

No explanation has been given as to why the network suddenly decided to change the schedule at the last minute. "Castle" season 8 was originally meant to have a lengthy hiatus during the mid-season break until this was changed to Jan. 4 and now it has been altered again to its original two-month break.