When Mike makes light of all the work that Molly is putting into planning their wedding Molly decides to let Mike take over and plan the whole wedding on his own. Mike's solution, much to Molly's chagrin, is to suggest they elope instead. In the meantime, Mike, Molly and Carl must rush Carl's new girlfriend, Christina, to the ER after Mike forgets to inform Molly, who is cooking dinner for the four of them, that Christina is allergic to nuts.