Mahou Shoujo Lyrical Nanoha: Detonation

Kyrie Florian's desperate attempt to save her father and dying homeworld collapses when Iris betrays her and takes the power gathered from Nanoha and the other defenders of Earth. Iris's true target is Yuri Eberwein, a powerful being sleeping on Earth and the focus of a grudge rooted in a tragedy from long ago.

Nanoha, Fate, Hayate, and their allies refuse to let the conflict consume Kyrie, Iris, and everyone around them. As hidden memories reveal what truly happened in the past, increasingly destructive battles force Nanoha to seek a way to stop Iris without abandoning the people whose pain drove the crisis in the first place.