Season 1

Pyontaro, Hiroshi and Tsubame — the Small 3 — load up an odd disc from their teacher. When they're not looking, Pyontaro's little sister Futaba vanishes.

Stranded in a new world, the Small 3 realize they have incredible powers. They meet other versions of themselves and learn how this reality differs.

Futaba's abductors subject her to tests, but she just wants her big bwudder. The Small 3 continue the search for Futaba and encounter a tense standoff.

As college student Segami struggles with his dystopian world, a hot schoolmate hands him an enticing flyer. Hoping to meet girls, he finds something else.

With his mind in a whirl, Segami runs into the Small 3. They witness a bold fighter pilot pit his life against an alien ship. Will it light a fire?

The Rebellion announces a guerrilla attack in Shibuya and Segami resolves to join. Meanwhile, a distraught Futaba stumbles upon a furry winged creature.

Aliens surround a sleeping Futaba! In Shibuya, Segami and his comrades fight fiercely but lose ground. As he retreats, he spots Tashiro under attack.

Futaba faces off against a squad of alien soldiers to protect her new friend. Facing heavy losses, Segami and the Rebellion turn to their secret weapon.

Genius commandeers an alien walker and leads a counterattack. But two fearsome alien soldiers are en route. Meanwhile, Doc and the others seek answers.

As the Small 3 soar toward Shibuya, Genius runs out of options against a relentless alien warrior. Reinforcements arrive — but will it be enough?

The "Small Three" arrive as live-streamed reinforcements to battle alien invaders, save Futaba, and officially debut as "THUNDER 3".

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