The episode starts out when Cam, Bones and Booth are examining an air conditioning unit that contains the results of damaged human remains. Bones looks visibly upset with Booth following the events of last season's finale. As Bones goes to examine the remains, Cam warns Booth that he is about to lose Bones.
Actor Freddie Prinze. Jr (Danny Beck) married and worked with Sarah Michelle Gellar on Scooby Doo, and David Boreanaz used to work with Sarah on Buffy the Vampire Slayer. Both times, they played a couple (Fred and Daphne, Buffy and Angel)
At the end of the episode, the clock flashes the time, "4:47." Which was seen when Pelant switched Booth and Brennan's alarm clock in The Past in the Present