Hajime Ichinose is a rather eccentric schoolgirl who is obsessed with notebooks. One day, she is approached by a mysterious man named JJ who pulls out a journal called a NOTE from her body, declaring her to be the new member of the elusive Gatchaman team. She later follows the words appearing in her NOTE to the mall, where a Gatchaman named Sugane Tachibana manages to defeat an alien that had disguised herself as a human. Later that day, Sugane brings Hajime to the Gatchaman's hideout where she meets the other members, Joe Hibiki, OD, Utsutsu, and their leader, Paiman. Sugane explains that their duty is to protect Earth from a hostile alien race known as the MESS that has been abducting humans. Hajime and Sugane are soon called upon by JJ to fight a MESS at the bus station, during which Hajime transforms for the first time, whilst a mysterious figure watches.