Lincoln dreams of having a cool older brother, and Lisa invents "Ro-Bro", for him. Ro-Bro is a blast until he bullies Clyde, and Lincoln realizes he has everything he needs in his "brother from two other fathers," Clyde McBride.

Lincoln decides to tap out of his brotherly duties and go on a vacation. Clyde steps in to take on Lincoln's role in the family, at first everything goes great, until tides turn and Clyde has to call on Lincoln for help.