he fourth season of Chuck was announced on May 13, 2010. Having initially ordered 13 episodes, NBC ordered an additional 11 on October 19, 2010 for a total of 24 episodes. Throughout the season, Chuck faced individual villains: Alexei Volkoff, head of Volkoff Industries, and Volkoff's daughter, Vivian McArthur.

Josh Schwartz and Chris Fedak expressed a desire to continue the series past the fourth season as early as March 2011, when it was announced that the season finale would be titled "Chuck Versus the Cliffhanger". The episode, as the title suggests, had a cliffhanger ending leading into the fifth and final season, which was ordered on May 13, 2011.

Overview from themoviedb.org