Shinpei Natsuki is a run-of -the-mill high school boy, who just so happens to have a new housemate, foreigner Yuha Maria, nicknamed UFO-chan. Turns out she lives up to her name, as she is a Space Officer sent to Earth to track down rogue alien species who are attacking other planets. Shinpei reluctantly joins Yuha on frequent trips back and forth in time in her UFO, to prevent the future from hostile alien takeover, all in the while getting his memory wiped to protect Yuha's secret. In the lower margins is a short strip titled "Professional" about a hitman sent to take down the mob boss Calpis...