Season 1 of Fault!! premiered on November 20, 2009.

During the summer, Sugiyama travels with his fellow tennis team members to a remote training camp. While there, his step-sister Mio has other training in mind. However his doubles partner Saeki has something else on her mind after seeing their training.

Season 2 of Fault!! premiered on February 22, 2013.

After a tumultuous summer vacation, Shuuichi begins the second school term while under the constant love assault from Ai and Mio. One day the tennis club leader Reiko announced that they will participate in the school festival at the end of the month, which they decided to run a cosplay cafe after much wrangling. Afterwards, she decided that she wanted to run as a candidate for next term's student council. That wasn't the end of his tumultuous days as a transfer student suddenly appeared in his class...