Dr. Donald Mallard or Ducky (David McCallum) will see some action when the long-running CBS series "NCIS" returns after its winter hiatus.

According to TV Line, the medical examiner extraordinaire will be called to perform a remote autopsy on a deep-sea diver who is reportedly murdered by his friends. While this may seem like a walk in the park for Ducky, the fact that he has to do the postmortem in a dive chamber makes it more exciting. The dead diver needs to be examined immediately and the Naval Criminal Investigative Service (NCIS) just cannot wait until the body is recovered and brought to the surface.

Ducky will be in a precarious situation, as the victim's colleagues are also being detained there. One of them is the killer and any inkling that the NCIS has discovered exactly what took place deep in the sea may send him in a killing spree. Ducky needs to be very careful or else, his could be the next body to be recovered from that hell hole.

During the winter finale, viewers also enjoyed a Ducky-filled episode, as the medical examiner searched for his long-lost brother. All these years, Ducky thought that his sibling was long dead. The arrival of a person who claimed he knew something about his brother led Ducky to the realization that he may still be alive. The episode ended with an emotional reunion between the two.

The finale provided a glimpse of Ducky's backstory, when he was still a young doctor serving in a military hospital. His relationship with his brother was also in focus, as viewers learned that he practically raised his sibling. When the younger Mallard suddenly went missing and then presumed dead, Ducky was heartbroken and not a day went by that he did not think of him.

"NCIS" season 13 midseason premiere (episode 12) will air on Tuesday, Jan. 5, at 8 p.m. EST on CBS.