High schooler Kei Kusanagi witnesses a UFO landing and later discovers its pilot, Mizuho Kazami, has been assigned as his new homeroom teacher and has moved in next door. When their secret is nearly exposed, Kei blurts out that they're already married, a lie he backs up by revealing he's actually eighteen despite his fifteen-year-old appearance, a side effect of the rare illness that puts him into comatose "standstills." The arrangement becomes a real marriage neither of them expected, one they now have to hide from Kei's jealous classmates and Mizuho's own Federation superiors. This manga retells the television series' premise with its own comic exaggeration, diverging from the anime as it goes.