NCIS investigates the death of a retired Navy officer who's son was convicted of a murder 16 years before. A flawed forensic test from that time can prove whether the son was the real murderer or innocent of the crime.
DiNozzo is reunited with his ex-girlfriend, Jeanne Benoit, when insurgents in South Sudan attack a group of volunteer doctors, including her husband. DiNozzo and McGee travel to the crime scene for the joint murder and kidnapping case and join the search for the missing doctors. Jon Cryer and Scottie Thompson return.
A Petty Officer, accused of killing an ex-girlfriend, is set free on mistrial. Professing to be innocent he asks NCIS to investigate and if necessary court martial him. Bishop and her husband have marital problems.
The Secretary of Defense turns to NCIS to help a sailor dying from leukemia locate a bone marrow transplant after two of his siblings are killed in the line of duty. Meanwhile, Bishop returns home to Oklahoma for Thanksgiving after learning of Jake's cheating.
After Ducky is attacked by a man claiming to have information about his half-brother who died decades ago, the NCIS team searches for the perpetrator, as Ducky recalls the final emotional days he had with his sibling. Also, with the holidays approaching, Bishop and Jake (Jamie Bamber) discuss the future of their relationship. Adam Campbell returns as "Young Ducky."
A family owned mortuary ordered a bunch of caskets from an overseas company. When they go to unload the shipment, they find that one of the caskets already has a dead body. There are ties to a prison break of someone NCIS helped put away.