Plein’s set was a pastiche: of Lewis Carroll magic mushrooms, of a giant garden troll with “pimp” spelled out across his shirt and Plein’s double-P logo on his hat, of ice cream trucks, of a bare-chested landscaper, and of sudsed-up shirtless car wash men. A quartet of young kids scampered around eating candy and knocking over a lamppost, oblivious to the NC-17 lyrics on the sound system. The handymen who fixed that lamppost wore shirts. Giant carnival swings towered over it all. Every Plein’s show is an event, He had a roller coaster on his Fall 2015 runway. A year before that he hired Rita Ora to emerge from a smoking car and sing “Facemelt.” This time it was Fergie and friends who kicked things off, propped up on the back of a low-rider convertible.