The story opens with the sudden appearance of Rukia Kuchiki in Ichigo Kurosaki’s bedroom. She is surprised at his ability to see her, but their resulting conversation is interrupted by the appearance of a “hollow”, an evil spirit. After Rukia is severely wounded while trying to protect Ichigo, she intends to transfer half her powers to Ichigo, hoping to give him the opportunity to face the hollow on equal footing. Ichigo unintentionally absorbs almost all her powers instead, allowing him to defeat the hollow with ease.
The next day, Rukia appears in Ichigo’s classroom as a transfer student. Much to his surprise, she appears to be a normal human. She theorizes that it was the unusual strength of Ichigo’s spirit that caused him to absorb almost all her powers, thus leaving her stranded in the human world. Rukia has transferred herself into a gigai — an artificial human body — while waiting to recover her abilities. In the meantime, Ichigo must take over her job as a Soul Reaper, battling hollows and guiding lost souls to Soul Society…

Info source (wikipedia)
Official Dentsu BLEACH website
Official TV Tokyo BLEACH website
Opening Theme:
01: “*~Asterisk” by Orange Range ( eps 1-25 )
02: “D-tecnolife” by UVERworld ( eps 26-51 )
03: “Ichirin no Hana” by High and Mighty Color ( eps 52-74 )
04: “Tonight, Tonight, Tonight” by Beat Crusaders ( eps 75-97 )
05: “Rolling star” by YUI ( eps 98-120 )
06: “ALONES” by Aqua Timez ( eps 121-143 )
07: “After Dark (アフターダーク)” by Asian Kung-Fu Generation ( eps 144-167 )
08: “CHU-BURA” by Kelun ( eps 168- )
Ending Theme:
01: “Life is Like a Boat” by Rie Fu ( eps 1-13 )
02: “Thank You!!” by HOME MADE KAZOKU ( eps 14-25 )
03: “Houkiboshi (ほうき星; Comet)” by Younha ( eps 26-38 )
04: “Happy People” by Skoop on Somebody ( eps 39-51)
05: “Life” by YUI ( eps 52-63 )
06: “My Pace” by SunSet Swish ( eps 64-74 )
07: “Hanabi” by Ikimono-gakari ( eps 75-86 )
08: “MOVIN!!” by Takacha ( eps 87-97 )
09: “Baby It’s You” by JUNE ( eps 98-109 )
10: “Sakura Biyori” by Mai Hoshimura ( eps 110-120 )
11: “Tsumasaki (爪先; Tiptoe)” by Ore Ska Band ( eps 121-131 )
12: “Daidai (橙; Bitter Orange)” by chatmonchy ( eps 132-143 )
13: “Tane wo Maku Hibi (種をまく日々)” by Atari Kousuke ( eps 144-154 )
14: “Kansha (感謝; Gratitude)” by RSP a.k.a Real Street Project ( eps 155-167 )
15: “Orange (オレンジ)” by Lil’B a.k.a MIE&AILA ( eps 168- )