The narry/hitch/potatoes parent trap au would have to involve Gerry and Mitch meeting at band camp and deciding to switch places until narry agree to reconcile. Mitch does just fine drumming for Niall’s band (even though he balks at wearing a paddy cap). But Gerry’s a bust as Harry’s lead guitarist. Harry confronts Niall and demands that he return Mitch, somewhat for the guitar parts but mostly because Harry’s going a little mad without somebody to cuddle him.

Mitch and Gerry refuse to switch back until Niall and Harry take all of the band members on a camping trip. Their ulterior motive is to scare off Harry’s fiancee (I assume this is Nick Grimshaw) with a series of increasingly preposterous pranks. Probably this culminates with Nick floating away on an air mattress wearing a sleep mask and posh boxer shorts and his Britney tee.

idk the denouement but it involves polyamory.