The season premiere was watched by 17.42 million viewers,[1] picking up two months after Gibbs and McGee were last seen fighting a group of rebels in Paraguay and focused on the aftermath of those events.

This season included a three-episode arc revolving around serial killer Gabriel Hicks, the episodes being: "Burden of Proof", "Keep Your Friends Close", and "Keep Your Enemies Closer".

In another central casting announcement, TV Line reported on October 4, 2017, that founding NCIS actress Pauley Perrette would be leaving the role of "Abby Sciuto" after the conclusion of season fifteen.

[8] In the midst of a storm that has shut down Washington, DC and knocked out power, the NCIS team investigates the kidnapping of a sailor, which sends Torres and Bishop out to sea to track evidence.

After Reeves sees his friend get kidnapped, the NCIS team discovers the primary suspect disappeared two days ago with confidential military information.

Looking over Reeves' dead body in the autopsy room, Abby vows to carry on his wish to start a charity in his native London, deciding to leave NCIS to do so.

Sara Netzley of Entertainment Weekly said, in reference to the positive changes, "now here's the show we’ve enjoyed for years", noting that it was "dark and twisty", giving it an 'A' rating.