After spending their first year of high school in peace and quiet, Haruka and Makoto run into Nagisa, a new student who was a member at a swimming club with them when they were kids.  That swimming club is being torn down, so the three of them sneak in to dig up a time capsule that they buried in the back, which is when they are reunited with Rin, the fourth member of their group who left to study abroad.
That's why you have 
to swim in the relay.
Deshalb musst du 
in der Staffel schwimmen.
Tiene que ser un relevo.
Tienes que participar en los relevos.
C’est pour ça que 
tu dois faire le relais.
Ecco perché devi partecipare alla staffetta.
É por isso que você precisa
 participar do revezamento.
Поэтому ты должен участвовать.