The history is placed right after the -cliffhanger- end of Godannar when Anna looks surprised to see Mira driving the Neo Okusaer.

Five years ago, while battling an alien force known as the "Mimesis," Dannar pilot Goh Saruwatari first met Anna Aoi. Today, on the day of their wedding, the ceremony is interrupted when the Mimesis strike again. As Goh struggles in his battle against the alien threat, Anna stumbles upon a top secret robot known as the "Neo-Okusaer" and uses it as a last-resort to save her fiancee. At that moment, Dannar and Neo-Okusaer merge to become the mighty robot "Godannar."

During her summer holiday at her grandparents house Tamai Shiina, a young and cheerful schoolgirl, meets a strange looking creature. They befriend each other and Shiina names it "Hoshimaru: The Round Star." When Shiina returns home after the summer to go back to school, she starts meeting other kids that also have befriended a strange creature like Hoshimaru. But she soon finds out that not all these creatures and their masters are as friendly as Hoshimaru.

The world of psychology is far from strange to the unusual Dr. Ichirou Irabu, a resident psychiatrist of Irabu General Hospital. He and his charming nurse Mayumi run through several patients, each suffering from a mental illness that harms their everyday life. Patients should be wary of the seductive Mayumi, with her spellbinding looks and devilishly short pink nurse uniform. On the other hand, the doctor seems to have three separate personalities: a child with an oversized lab coat; an intelligent, youthful man with feminine traits; and a selfish, outgoing green bear. While curing his patients in questionable ways, Dr. Irabu often tries to gain something from them outside of his profession—and in doing so, occasionally forgets his role as a doctor. As each patient struggles to face the nature of their distress, an obvious yet invisible thread ties their paths together.