When Carly jokingly challenges MMA fighter Shelby Marx to fight, the two agree to have an exhibition fight for charity. Unfortunately, Carly accidentally falls on Shelby's grandmother during a press conference. Thinking Shelby wants revenge, Carly backs out of the fight, only to be ridiculed as a coward.

Carly visits Shelby and apologizes, and the fight is back on. However, when Nevel Papperman alters a clip of the press conference to make it look like Carly intentionally tackled Shelby's grandma, Shelby becomes furious and genuinely attacks Carly during their boxing match.

Spencer comes to the rescue when a heat wave hits Seattle and the power goes out.

One Direction has accepted an invitation to perform on iCarly. Band member Harry becomes sick and Carly dotes over him. Realizing Harry is playing sick for the attention, they hatch a plan to get him back in the group by telling him Gibby has become their newest band member. Meanwhile, Spencer becomes a personal trainer and gives a bratty girl a makeover.

Carly is sad when her father cannot escort her to a military dance. Sam and Spencer fix a motorcycle. Gibby gets his head stuck in an "artificial head machine" (because he sold his first one at the pawn shop). Freddie gets a new phone.