Some unidentifiable and gruesome remains were lodged in the pinsetter at a bowling lane and evidence suggests foul play. Booth and Brennan go undercover in a bowling league with the help of Brennan's father Max, who used to be in the victim's bowling team. Meanwhile, Angela works from the hospital via webcam as she comes closer to giving birth. The episode ends with Brennan telling Booth that she is pregnant and that he's the father of her unborn child.