Megatron Rising (1) Transformers: Animated : Season 1 Episode 15

When Starscream, Blitzwing, and Lugnut begin their invasion upon Earth, Optimus Prime demands that Sari hand over her key. This causes her to run away only for her to end up captured by Dark Black Arachnia. Optimus begins to doubt his leadership when Megatron begins his next stage to have his body rebuilt.