The Description:
 The story opens with the sudden appearance of Soul Reaper Rukia Kuchiki in Ichigo Kurosaki's bedroom. She is surprised at his ability to see her, but their conversation is interrupted by the appearance of a "hollow", an evil spirit. After Rukia is severely wounded while trying to protect Ichigo, she attempts to transfer half her powers to Ichigo in order to let him face the hollow on equal footing. Ichigo instead unintentionally absorbs almost all her energy, allowing him to defeat the hollow with ease. The next day Rukia appears in Ichigo's classroom as a seemingly normal human, and informs Ichigo that his absorption of her powers has left her stranded in the human world until she recovers her strength. In the meantime Ichigo shelters Rukia in his home and takes over her job as a Soul Reaper, battling hollows and guiding lost souls to the afterlife realm known as Soul Society.
 After a few months of this arrangement, in the sixth volume of the series, Rukia's Soul Reaper superiors find out about her giving her powers away (which is illegal in Soul Society) and send a detachment to arrest her, and sentence her to death. Ichigo is unable to stop Rukia's capture, but with the help of several of his classmates who also possess spiritual abilities and ex-Soul Reaper and captain Kisuke Urahara, he sets off for the Soul Reaper base, located in Soul Society. Once there, Ichigo and company battle against the elites of the Soul Reaper military, and are ultimately successful in halting Rukia's execution. (The material was taken from wikipedia.org)