An anti-monarchist rebellion has gained traction in the Equestrian outskirts. Fearing a challenge to her power, Celestia commissions a weapon unlike anything seen before.

Twilight Sparkle combines science and magic to split the atom, but seeing the destructive potential of her research gives her a change of heart.

Stuck in Canterlot under the watchful eye of Celestia and her secret police, Twilight must inform the rebels of the bomb's existance before it is too late.