Burned

S5 E22: When a CSI's personal problems taint an investigation, Horatio must fire a member of his team. An arson home fire, leaving one man dead and nearly killing his fiancé, leads the CSIs to the fiancé's ex-boyfriend, who is obsessed with ruining the couple's life. After discovering two burned cadavers in the home, the CSIs must determine if the fire was a cover up or the couple's perilous attempt to fake their own deaths and give up everything to start over.