Ichigo fought the leader of the guys in green, Gan Ryu...
Whist in Seoul Society, to prevent the collision between it and the real world, General Yamamoto give the command to fire the gigantic Kidou Canon at the new dimension. And the new dimension begins too collapse.
Rukia uses her Zanpakutou in the fight. However her opponent multiplied, luckily her big brother Captain Byakuya came and destroy the opponent with his Bankai - Senbonzakura Kageyoshi.
In the finale Ichigo vs. Gan, Ichigo cuts him in half
Ichigo saved the new shinigami girl but the collision between the two worlds did not stop. So how to stop the collision?
Watch Part 4 of The Bleach Movie - Memories of Nobody above, to find out (be patient, wait for it to buffer).