While Nagato was personally escorting a group, people from Amegakure joined forces with Root's emissaries and suddenly attacked. Not only did they kill a large number of the members remaining at Akatsuki's camp, but they also captured Konan.
However, killing some people to weaken Akatsuki was not Hanzō's objective. He intended to wipe out Akatsuki completely, so after capturing Konan, he left a threat for Yahiko.
If he wanted his companion back, he and Nagato were to go to a certain location in the Land of Rain by themselves, without bringing anyone else.
Hanzō knew that Akatsuki's leader was Yahiko. Konan and Nagato were also relatively important, but their importance within Akatsuki fell short of Yahiko's. Still, once all three were dealt with at once, Akatsuki would not be far from falling apart.
Hanzō also asked Danzo to lead his Root in another attack on Akatsuki's camp after Yahiko left.
All of this involved both Hanzō's own ideas and the interference of Obito Uchiha and White Zetsu. Without White Zetsu sowing discord on the sidelines and giving things a push, relations between Amegakure and Akatsuki would not have deteriorated so badly.
"Obito, Obito, that guy finally died!"
After the pitcher plant poked his head out of the ground, he immediately said to Obito Uchiha in a strange voice, "He died at his companion's hands. How tragic! And he even offered himself up..."
Before White Zetsu could finish, Black Zetsu reached out and gave him a twist from behind. He had figured it out: White Zetsu ruined things because he had a mouth. He always brought up the sorest subjects. Was he reminding Obito not to forget Rin Nohara's death?
Obito Uchiha ignored White Zetsu's foul mouth and said coldly, "Is that so? Then the plan can proceed."
Akatsuki had suffered