20-Squad must leap into action when Yakuza assassins descend on L.A., targeting a number of mysterious Japanese ex-pats. Meanwhile, Nichelle finds her job on the line at the inspector general's office when a colleague accuses her of taking bribes.

While training with Long Beach SWAT, Street discovers a biker club has stolen a cache of armor-piercing bullets and brings 20-Squad into the hunt for the gang before they can pull off a daring and deadly heist. As Hondo struggles with changes at work, Nichelle finds herself at odds with her former colleague Bruce.

Tan finds himself on a one-man mission to save his new love interest and her journalist co-workers when mercenaries take over a black-tie correspondents' dinner. After the group escapes, it's up to SWAT to track down the well-trained gunmen.