The team investigates when two Navy corpsmen are murdered while responding to a call. They realize that one of them is missing his credentials. Two more Sailors turn up dead, and a heart intended for transplant is destroyed.

The heart was intended for a Navy civilian cryptologist, Max Pinzon. Brody's mother Olivia, who works for DARPA, acts as an intermediary. Patton Plame bonds with the young programmer over their skills and health issues as the others investigate whether this was a targeted assassination attempt.

They eventually realize that the heart was stolen. Pinzon is part of an extremely rare blood group, and someone else with the same phenotype is in need of a heart. They eventually discover that the culprit is long-time criminal Thomas Dolan, who is working with a gun-for-hire named Gaylan Conroy.

With the help of both Olivia and Pinzon, they locate Dolan, Conroy, and the heart. Conroy is arrested, but the heart is already in Dolan. Unfortunately, Dolan didn't survive the operation and is now brain dead. To make matters worse, the heart is very nearly unviable by this point.

With time of the essence, Dolan is airlifted to the hospital, and Pinzon is taken into transplant surgery. Despite everyone's best efforts, Pinzon dies anyway.

Patton decides to finish Pinzon's code project to honor the young man's last wishes.