A second-year high school boy finds himself uneasy during Christmas time due to an experience in the past. However, this year at Christmas, he gets his last chance to ask out a graduating female senior named Haruka Morishima — or one of several other classmates. The story of the anime will be arranged in an omnibus format, with each heroine getting her own version of the story animated. Each heroine will sing her own version of the ending theme song.

Amagami SS+ continues to follow the life of Junichi Tachibana after the events of Amagami SS. Much like its predecessor, it is arranged in an omnibus format. Each character arc receives two additional episodes which expand on Junichi's relationship with each girl following the closing episodes of Amagami SS.