Ep. 17: Ryuko learns Senketsu's origin while Satsuki rebels against Ragyo's Life Fiber sacrifice plan.

Mako and Senketsu intervene in the conflict between Ryuko and Tsumugu. Aikuro reveals that Tsumugu's sister Kinue died during a Life Fiber experiment, and explains that Senketsu was created using Ryuko's DNA, which is why she is the only one capable of wearing and communicating with him. Concurrently, Honnouji Academy organizes a cultural and sports festival to honor Ragyo's visit. Ryuko discovers this event is a cover for a final experiment intended to sacrifice the entire Honnouji City population to the Life Fibers. She and her allies rush to Honnouji as the ceremony commences. While Ragyo initiates the Life Fibers to consume the stadium attendees, Ryuko's group arrives. Satsuki then stabs Ragyo in the back, declaring her rebellion against her mother and the Life Fibers, exposing this betrayal as the true purpose behind her establishment of Honnouji Academy.
Episodes
- Ep. 13 · Ryuko loses Senketsu to Nui while Satsuki prepares for a major raid across multiple cities.
- Ep. 14 · Ryuko recovers Senketsu's pieces while battling the Elite Four in Kansai.
- Ep. 15 · Satsuki battles Kaneo Takarada in Osaka while Ryuko arrives to confront her.
- Ep. 16 · Satsuki organizes a festival to distribute Life Fiber clothing while Ryuko learns the truth about Senketsu.
- Ep. 17 · Ryuko learns Senketsu's origin while Satsuki rebels against Ragyo's Life Fiber sacrifice plan.
- Ep. 18 · Ragyo reveals her true identity and defeats Satsuki while Ryuko battles Nui.
- Ep. 19 · Raindrops Keep Falling on My Head
- Ep. 20 · Ryuko confronts Nui and is forced into Junketsu while Satsuki escapes confinement.
- Ep. 21 · Satsuki and Senketsu struggle against Ryuko while Nui reveals Junketsu is fused to her Life Fibers.