After a vice admiral's laptop is infected with ransomware, he enlists McGee and the NCIS team to track down the hacker before the computer virus eliminates his personal and professional files forever while Alex takes time off to assist her mother, Marie Quinn after she receives a "911" text.
- Alexandra Quinn's mother, Marie Quinn, is introduced for the first time.
- It is revealed that Marie Quinn is suffering from dementia. This ultimately would result in Alex taking an extended leave of absence with the Season Fifteen premiere.
|Leroy Jethro Gibbs||Mark Harmon||Special Agent in charge of the NCIS Major Case Response Team.|
|Abigail Sciuto||Pauley Perrette||Chief Forensic Specialist for the NCIS Major Case Response Team.|
|Timothy McGee||Sean Murray||Senior Special Agent and second-in command of the NCIS Major Case Response Team.|
|Nicholas Torres||Wilmer Valderrama||Special Agent for the NCIS Major Case Response Team.|
|Alexandra Quinn||Jennifer Esposito||Special Agent for the NCIS Major Case Response Team.|
|Eleanor Bishop||Emily Wickersham||Probationary Agent for the NCIS Major Case Response Team.|
|James Palmer||Brian Dietzen||Assistant Medical Examiner for the NCIS Major Case Response Team.|
|Leon Vance||Rocky Carroll||Director of NCIS.|
|Donald Mallard||David McCallum||Chief Medical Examiner for the NCIS Major Case Response Team.|
|Clayton Reeves||Duane Henry||Officer with MI6.|
|C. Clifford Chase||Bruce Boxleitner||Vice Admiral.|
|Marie Quinn||Mercedes Ruehl||Alex's mother.|
|Clint Asher||Philip Smithey||Main murder victim.|
|Carlo Hackett||Michael Drayer||Serial Killer responsible for the ransomware.|
|Reese Goldman||Raychel Diane Weiner|
|Ian Lipovetskiy||Craig Robert Young|
|Allison Archer||Erica Shukrani Luttrell|
|Lazlo Downey||Andrew Bridges||Lieutenant in the United States Navy.|
|Jorge||Gabriel Baca||Uncredited role.|