The Voices of a Distant Star (about 25 minutes)
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Written and directed by Makoto Shinkai. This short film was originally released in 2002. I first saw it in 2023, as a bonus feature on GKIDS' Blu-ray release of 5 Centimeters per Second. I feel I should say that most sites don't include "The" as part of the title, so I'm assuming it wasn't part of the original English release of the short two decades before I saw it, but it is included in the release that I saw (at least onscreen), so that's what I'm calling it here.

There are two teenage friends, a girl named Mikako and a boy named Noboru. When Mikako is recruited into the UN Space Army to pilot a mecha and battle aliens called Tarsians, she sends e-mails to Noboru, which he reads on his cell phone. (We hear alternating voiceovers of both characters reading the letters.) The farther Mikako gets from Earth, the longer it takes for her letters to reach Noboru. Eventually she goes to another star system, at which point the friends are separated by eight years.

There's not much else I can say about the plot, but it's a poignant story. I feel like I should say more than just "it's poignant", but I really don't know what else to say. I did like the short, though.