A lazy gym teacher Seong Geun is completely content with his easy gig teaching high school P.E, but times are getting tough and his job is in danger. When Seong Geun's school decides to sack a gym teacher in favor of an English teacher, he too makes an important decision. To survive, he must teach English! Seong Geun whole heartedly makes the switch from PE to ET (English Teacher), but there's only one problem: he doesn't speak English.