The story happens before the Wolgarm incident. Emilia while walking towards the garden meets with Rem, Emilia mentions that she must go to the garden to talk with the spirits since the commotion Subaru made interrupted her last attempt, Rem offers to "deal" with Subaru and asks if she should not say where Emilia is heading to if she finds Subaru, Emilia replies that such action is not needed and says that Rem can tell him where she is heading to if he asks.
Emilia decides to go to the forbidden library to get Puck back from Beatrice before going to the garden. While at the library she speaks with Beatrice and asks her if she would like to look at the stars with her and Subaru, she mentions Subaru has taught her a whole lot about stars, some of them being Altair, Vega and Betelgeuse, which she mispronounces as Petelgeuse; the last name causes a reaction out of Beatrice and she kicks Emilia and Puck out of her library.
Outside in the garden, she talks with Puck and mentions that Subaru told her his name is inspired on stars and can mean "Pleiades" from where he came from, she also said he taught her the story behind the Altair and Vega stars during Tanabata. Shortly after she finishes the story, Subaru appears, meaning that soon after, another sky classroom was about to begin.