Miguel Martinez, a famous club promoter, is found stabbed to death. As he is a citizen of Spain, and the son of a diplomat, a CSI from Barcelona is called in to help investigate the case, which causes Mack no end of grief. He tells the Spanish investigator to lay off CSI: NY's turf once he realizes that the victim is the investigator's nephew.
The victim's girlfriend, Natalia Sanchez, is interrogated at the Spanish consulate. When she discovered the body, the first thing she did was call Miguel's mom in Spain. She was then told to go to the consulate where they'd take care of everything.
Mack notices that the evidence doesn't add up. Some suspicious details point to the crime not being a homicide at all. The team finds out that Miguel had a fight with a drug dealer earlier in the club, but the dealer denies killing him.
A solar panel piece found at the crime scene has blood which doesn't belong to the victim. The blood is traced to a homeless man who was in Miguel's apartment earlier. He confesses that Miguel paid him to murder him, but at the last minute the homeless man chickened out.
Natalia tells the team that Miguel asked her to help him commit suicide and to make it look like a murder so his mother wouldn't find out. Natalia was reluctant to help with his plan, but she got to the apartment too late to stop him.