DearS opens one year after a UFO carrying 150 aliens crashes off the shores of Kasai. Unable to repair their ship, the Japanese government assigns the stranded visitors the label “DearS” and folds them into society as Japanese citizens, teaching them the language, customs, and culture they need to survive on Earth. To ease that transition, a home-stay program places DearS guests in ordinary households, turning everyday life into an uneasy experiment in coexistence between humans and aliens.
For high school student Takeya Ikuhara, that new reality is a nightmare. He distrusts the DearS and wants nothing to do with them, but everything changes when a truck carrying one of the aliens’ capsules drops it by a riverbank and the girl inside is released from confinement. Takeya saves her from being hit by a truck, names her Ren, and discovers that she has imprinted on him as her “Master” while becoming his personal “Slave.” Ren refuses to leave his side, and Takeya’s quiet life is pulled into the strange, chaotic world of the DearS, where the line between hospitality, dependence, and chaos grows harder to control.