Horatio is transported back to Miami to help the team find Calleigh, who's been kidnapped and forced to cover up a murder. While at the scene of the kidnapping, they notice that an ambush took place, involving Calleigh fainting from chloroform. Later on, one of the kidnappers turns himself in to the CSI's and tells them the location of Calleigh... but to arrest the remaining kidnapper without Calleigh becoming a victim, they cook up a poker plan, hoping that the kidnapper will "fold" after "all in".