Kayo Fujikawa has been acting strange recently, leading her clubmates Ayame Seki and Shiina Murakami to worry about her. Moreover, her birthday is just around the corner. To lighten the mood of their precious companion, Ayame and Shiina take it upon themselves to make sure that Kayo enjoys her special day. Set before the time Tamaki Honda joins the SNS club, this extra chapter of Stella no Mahou follows the club seniors as they develop their friendship.