Wikipedia
"Repilot" is the first episode of the fifth season of Community, and the 85th episode overall in the series. It originally aired on January 2, 2014 on NBC; and was written by series creator Dan Harmon (after he was re-hired to run season 5) and Chris McKenna and directed by Tristram Shapeero. This is the final episode of the series to feature Chevy Chase and the character of Pierce Hawthorne.
In this episode, Jeff Winger ( Joel McHale) returns to Greendale one year after graduation to research a potential lawsuit after his practice goes under. While doing this, he finds out what has happened to his friends within the study group since his departure.
The episode received positive reviews, with many critics noting showrunner Dan Harmon's return to the series after his absence from the fourth season; and 3.49 million viewers watched this episode and the following episode " Introduction to Teaching."