Ichigo Kurosaki is a teenager gifted with the ability to see spirits. His life is drastically changed by the sudden appearance of a Soul Reaper —one who governs the flow of souls between the human world and the afterlife—named Rukia Kuchiki, who arrives in search of a Hollow, a dangerous lost soul. When Rukia is severely wounded defending Ichigo from the Hollow, she attempts to transfer half of her reiatsu energy to Ichigo so that he can defeat the Hollow. However, Ichigo takes almost all of her energy, transforming into a Soul Reaper and allowing him to defeat the Hollow with ease. With her powers diminished, Rukia is left stranded in the human world until she can recover her strength. In the meantime, Ichigo must take over Rukia's role as a Soul Reaper, battling Hollows and guiding souls to the afterlife realm known as the Soul Society.
As time passes and Rukia has yet to return to the Soul Society, her Soul Reaper superiors learn about her whereabouts and actions and sentence her to death for performing the illegal act of transferring her powers. Although he is unable to stop Rukia's departure to the Soul Society, Ichigo resolves to rescue her with the aid of several of his spiritually aware classmates, Orihime Inoue, Yasutora Sado, and Uryū Ishida, and the ex-Soul Reapers Yoruichi Shihōin and Kisuke Urahara. Once at the Soul Society, Ichigo and company battle against the elites of the Soul Reaper military and strive to reach Rukia before her execution.
It is revealed that Rukia's execution and Ichigo's rescue attempt both had been manipulated by a high-ranking Soul Reaper, Sōsuke Aizen, who was previously believed to have been murdered, as part of a far-reaching plot to take control of the Soul Society. Aizen betrays his fellow Soul Reapers and allies himself with the strongest of the Hollows, the Espadas. Aizen thus becomes the main antagonist of the series, and the Soul Reapers form an alliance with Ichigo. At this point, Bleach chronicles the war between the Soul Reapers, the Espadas, and Aizen. After each of the involved's eventual defeats, Ichigo undergoes intense training to become strong enough to battle Aizen alone. As Aizen is weakened, a spell that Urahara had previously hidden within him activates and seals him, thus ending the conflict and leaving the Soul Society to imprison him. As a result of using all of his Soul Reaper powers to defeat Aizen, Ichigo loses them and becomes an ordinary human once again.
Seventeen months later, a group of human individuals, called "Xcution", emerges. They possess Hollow-like powers that allow them to draw out the soul that dwells in any substance, and they desire to be rid of them. To achieve this, they approach Ichigo and inform him that they want to restore his lost Soul Reaper powers so that they may transfer their powers onto him.
Informations Source: Wikipedia