住在新潟县长冈市的普通女高中生，三栖立翼。某天，在充满了平稳田园风光的她家附近，一艘正体不明的宇宙船坠落了。一之濑初等“立川CAGE”的G成员为了调查此事而赶来。在近邻住民的注视下，从宇宙船里出现的是将众多星球导向和平的异星人杜兰莎。翼与初等GATCHAMAN以及和平的使者杜兰莎的邂逅，将会给世界带来什么呢？

翼突然间成为了GATCHAMAN，但在那份天生的积极乐观下，她决定为了大家而以英雄的身份活动。为了给如今已成为当地名人的翼庆祝起航，大家在购物中心举办了壮行会。翼和被任命为指导者的初一起走上会场的舞台，但……。另一方面，在追寻神秘集团“VAPE”真正身份的累面前，红色CROWDS突然出现了。

等待着前往东京的翼和杜兰莎的是人气情报节目《MILLIONE屋》的特邀出演。两人以默契的交流展现出亲密的关系，在弥漫四周的祥和气氛当中，杜兰莎也露出了笑容。翼和立川CAGE剩下的G成员也打过了招呼，终于要开始身为GATCHAMAN的活动了。但就在此时，率领“VAPE”的男人铃木理诘梦在涩谷车站前开始了危险的行动。

为了贯彻自己坚信的正义，拯救即将消逝的生命，翼遵从内心的想法开始奔跑。她在背后被强力的风推进之下降落到战场上，和想法与自己重合的杜兰莎一同将聚集的敌人击溃，并赶去救援落败的同伴。这些情景通过电视转播传到全国，众人见证着她的英姿并发出支援，为新英雄的出现而欢呼沸腾。之后，为了结束这场争斗，翼发出拼尽全力的一击。

利用GALAX进行的首相公选手机选举终于开始了。在现任的菅山压倒性有利的预想当中，杜兰莎作为史上首位外星人首相候选也备受注目，然而其支持率依然停留在下位。但，杜兰莎通过气泡君的力量得知多数人抱有的某个强烈想法，于是他面对全国国民宣告了一个公约。这是，在立川CAGE的GATCHAMAN之间也产生意见分歧的宣言。

在手机投票中获得了多数国民的支持，杜兰莎首相诞生了。他迅速地吸收知识，并理解了这个国家现在的政治制度。于是，史上首位外星人首相的政权开始运转。政治家们由于自己的行事规则无法通用而不知所措。再加上杜兰莎毫无遗憾地发挥着自己外星人的特异性，开始推进至今为止没可能存在的超出常识的政权运营。

Japan undergoes rapid change as Gelsadra continues his reforms based on his slogan, "Our Hearts as One, Create Our World, Together." With his popularity on a meteoric rise, his constituents are full of smiles. Tsubasa firmly believes that their shared dream will soon come true, but some cannot help but feel a sense of disquiet over the rapidity of change...

Due to what happened to Gelsadra, the red speech bubbles suddenly produced mysterious life forms, which start appearing all over Japan and start interacting with everyone. The G members move out to deal with the mysterious beings, but things take a rather unexpected turn...

The general public has come to accept the Kuu-samas into society, and they seem to be helping with Gelsadra's wishes to help everyone become one. However, in order to make everyone become one, the Kuu-samas take the next step. The Gatchaman try to warn the public about the Kuu-samas and their actions, but they find out now that this has been set into motion, it's not easily stopped. The Gatchaman now consider Gelsadra and the Kuu-samas dangerous, which ends up making them unfavorable to the general public that loves both Gelsadra and the Kuu-samas...

Rizumu's ideal world slowly starts coming to fruition. The small opportunity presents itself, and is magnified, causing chaos to spread quickly. However, Gelsadra, who is in the middle of all of this, believes he is just doing what the people want and smiles, despite some terrible things that have occurred. Meanwhile, Tsubasa who had separated herself from the Gatchaman and Gelsadra goes back home to Nagaoka to face Yuru-jii and herself...

A massive throng of Kuu-samas assemble from all across the country and swarm the town, and the Gatchamans go all-out to take them out.

Having accepted the masses' wishes, the Gatchamen head to battle with a strong resolve to put everything they have on the line in order to grant them.