Ryn fights to maintain leadership of the pack when the other mermaids question her loyalties. Ben interferes in a mermaid ritual causing friction between himself and Ryn, meanwhile, Helen discovers more about her family lineage.
Ed finds himself behind enemy lines when he crash-lands on a mysterious planet. Meanwhile, Kelly questions why Gordon wants to take the Command Test.
Warner and Eli worry about their dads´ health, so the four guys visit the doctor to get physicals. However, when the doctor dies before giving Warner his test results, he begins to question his own mortality.
When guards at a Virginia prison intercept a package with evidence relating to the kidnapping of two boys several years ago, the BAU questions a notorious serial killer who may have information on the boys´ whereabouts.
In the season finale episode, Murtaugh is forced to question his loyalty to his own partner when Cole is investigated by the FBI. Meanwhile, Cole works a case that puts Natalie´s fiancé Andrew in the crosshairs, right before their wedding day.
Louis flies the entire family to Taiwan in an effort to make things right with Gene. Upon meeting Gene´s beautiful fiancé, Margaret, and seeing the wonderful life he has built for himself, Louis questions whether his life in Orlando is just as great as it could be in Taiwan. Meanwhile, Jessica takes Eddie, Emery and Evan to her favorite childhood locales, including Dihua Street and Shilin Night Market.