Natsu e no Tobira

is a 1975 Japanese manga by Keiko Takemiya as the early example of a shōnen-ai manga. It was originally serialized in Hana to Yume, published by Hakusensha, and it was re-released in 2000 by Kodansha. An animated film version of this manga was released on March 20, 1981 in Japan.

Plot
The plot is a coming-of-age tragic romance involving five children in a French academy: a young boy Marion begins an affair with an older woman; his friend Ledania has unrequited feelings for him; their friend Claude is secretly deeply in love with Marion; friends Lind and Jacques develop a dangerous rivalry over their love for Ledania.