Noriko Takaya's dream is to become a space pilot like her father, who died when she was young after an attack by alien forces in deep space. After entering Okinawa Girls Space Pilot High School, she must persuade everyone, especially herself, that she can fulfill her goal and become an accomplished pilot despite being just an ordinary girl.

This double feature comprises of "Gunbuster" and "Diebuster" (aka "Gunbuster 2") condensed into a single theatrical release told in two parts with a musical intermission in between. The 95-minute "Aim for the Top! Gunbuster" movie is a compilation of the original 6-episode Gunbuster OVA, where man first meets the insect aliens and builds fighting robots and huge battleships to combat them. Takaya Noriko and Amano Kazumi lead the fight, doing massive damage to the insect's world. The 100-minute "Aim for the Top 2! Diebuster" movie completes the series, with country girl Nono leading the "Topless" fighters to protect Earth from the invading insects.

Nono is a clumsy waitress who dreams of becoming a space pilot. One day, she meets Lal'C Melk Mark, a member of the elite psychic pilot team "Topless." But when space monsters appear from out of nowhere to wreak havoc on Mars, Lal'C calls out her Buster Machine—codenamed "Dix-Neuf"—to subdue the threat. During a battle with a Space Monster, Lal'C gets the surprise of her life when she sees Nono use her super-strength to help Dix-Neuf destroy the alien. From that point, Nono hangs along with Lal'C in hopes of becoming a member of Topless.