Takeya Ikuhara is an ordinary high school student going about his everyday routine. A year ago, a UFO carrying a group of beautiful alien women crash-landed on Earth, but Takeya has no interest in all the commotion surrounding them. These extraterrestrials, known as the DearS, have decided to make Earth their permanent home. What no one realizes is that the DearS are a slave species whose only purpose is to serve and please their masters. One day, Takeya spots a figure shivering behind some bushes. That figure is Ren, a DearS, and after Takeya saves her, she chooses him as her master. Takeya, unaware of the master-slave relationship that defines the DearS, tries to teach Ren how normal people live on Earth, though he constantly worries that she is an evil alien attempting to brainwash him. Ren, however, is unlike the other DearS—she is malfunctioning, and their leader is tracking her down. Meanwhile, Takeya begins to learn more about the DearS, and a legendary DearS bond known as the "Gift" starts to develop between the two of them.