Son Goku lands on a troubled continent, shortly after his fierce fight with Frieza on the planet Namek. Once on this strange "Earth"... Goku discovers of a power known as the Bijuu and that if he were to collect all nine, he would obtain the power to go home.. So says a mysterious masked man! So, Goku goes around casually blowing shit up for three hours before going back to Amegakure with all the barely living hosts. The Masked man then tries to kamui Goku, only for him to transform into super saiyan and the shockwave of that transformation killing him.
Next, the rest of the Akatsuki try to fight back but are defeated. Sasori is taken out by a headbutt, which evaporates his being. Deidara blows himself up, but fails to hurt Goku. Itachi uses amaterasu, only for it to miss and hit Konan. Pein then takes Itachi's soul in a blood lust. Zetsu, Kakuzu, and Hidan all charge Goku only to be hit with a kamehameha. And then Pein is defeated with a spirit bomb to Amegakure. Killing all of the Jin's too.
And then Kisame and Goku have a final fight in the ocean, which leaves Goku NEARLY dead and Kisame only half winded. Goku then apologizes and promises to never return to "Earth" and flies off.