While on a survey mission, the U.S.S. Enterprise discovers a comet is going to strike an inhabited planet. They try to re-route the comet, only to find that an ancient alien relic buried on the comet’s icy surface is somehow stopping them. As the away team try to unlock the relic’s secrets, Pike and Number One deal with a group of zealots who want to prevent the U.S.S. Enterprise from interfering.

The 118 races to the rescue when the 9-1-1 Call Center goes up in flames. Then, Bobby risks his life to save a trapped May, and Claudette, Buck and Eddie work together to help an injured electrician, and Chimney and his brother team up as firefighters for the first time.

McCall, Mel and Harry take a leap of faith when they help a self-proclaimed psychic, Julien, find his missing sister who he says is in imminent danger, according to his visions. Also, Delilah's PTSD returns as she struggles under the weight of keeping McCall's secrets and her worries about her mother's safety.

When a navy seaman is involved in a murder, the NCIS team is called to work the case on their day off. Also, Lucy finds out Whistler turned down a promotion in D.C. to stay in Hawai'i.

NCIS investigates a ring of clever teenage partygoers when a string of break-ins takes place at Marine Base Quantico. While working the case, Special Agent McGee forms a bond with one of the teens, Teagan Fields.

Facing his anger management issues, Owen has a breakthrough in therapy. Then, after a particularly devastating emergency call, Grace reaches out to a co-worker, but regrets when Judd offers more than she was planning. Also, a clown has an emergency at a young boy's birthday party, and Tommy, T.K. and Nancy race to help a survivalist who has a painful encounter with a reptile.

The members of the 118 race to the rescue of a social media influencer when she has an accident in a sauna, then to an emergency at a reality show wedding, and finally a tragedy when a mother and her daughter go hiking. Meanwhile, Maddie worries she has missed too many firsts with Jee-Yun, May questions Athena's career path, and Hen and Karen attempt to recapture the fun.

When Aunt Vi is the lone juror on a murder trial who believes the defendant is innocent, McCall covertly investigates the case to find proof that Vi's instincts are correct.

With Layla tracking down Harrow, Marc, Steven, and Khonshu must return to Cairo to stop Ammit as she looks to threaten humanity once more.

Marc & Steven search through their memories to find their truth or become left behind.