Ben, Gwen, and Grandpa Max attend a family wedding for Max’s nephew Joel and his bride-to-be, Camille. Before the day of the wedding, Ben interrupts a mud alien’s attempt to sabotage the wedding. Ben defeats the sludge alien as Cannonbolt but finds the groom’s parents pointing rifles at him soon after. He escapes with Gwen’s help, and Max explains that the groom’s side of the family are all Plumbers, while the bride’s side are all mud-like aliens, called “Sludgepuppies”, which the Plumbers were sworn enemies with until Joel and Camille met and forged a romance, which makes the wedding a truce. However, during a dinner time with the families, they are confronted by Camille’s ex-boyfriend.