Puppet Fight: 10 vs 100!

is episode 26 of the Naruto: Shippūden anime.

Synopsis
Sakura and Chiyo continue the battle with Sasori, who overwhelms them initially. Sakura manages to later destroy Sasori's puppet body, but he reforms back. Seeing this, Chiyo uses the White Secret Technique: Ten Puppet Collection of Chikamatsu, which Sasori counters with his Red Secret Technique: Performance of a Hundred Puppets. Sakura and Chiyo, with the help of her Ten Puppets seem to trap and defeat Sasori, but, under cover of the battle, Sasori secretly transfers the only living part of his body - his heart - into another puppet, and tries to attack Chiyo from behind. Sakura notices this and intervenes, forcing Sasori to stab her through her torso.