During routine manoeuvres near Hawaii in 1980, the aircraft-carrier USS Nimitz is caught in a strange vortex-like storm, throwing the ship back in time to 1941—mere hours before the Japanese attack on Pearl Harbor.

A battle-weary ex-Special Forces Operative buys a ranch in remote American West to flee from the world, and encounters a strange series of trespassers, including a beautiful elf princess and a Native American mystic and Orcs. When the Orcs invade his property, John must give up his isolation to become a hero, before the Orcs unleash their dragon god on our world.

本作主人公冈部伦太郎（宫野真守 配音）是个患有严重中二病的大学生，自称为“凤凰院凶真”的他和伙伴们组成了“未来发明研究所”，在位于秋叶原的一个简陋实验室内进行各种古怪发明和调查。 2010年7月28日这天，冈部和青梅竹马真由理（花泽香菜 配音）一同去了科学讲义会场，在那里，他们遇见了天才少女牧濑红莉栖（今井麻美 配音）。让人意想不到的事情发生了，冈部在会馆楼道内听到一声惨叫，他闻声而至，发现了倒在血泊中的牧濑。冈部用手机短信将这件事告诉好友桥田至，这个举动，让世界都颠覆了。实验室里那个所谓的“未来道具”，竟然真的可以左右世界的进程，冈部自此成了孤独的观测者。 这一切都是命运石之门的选择。

2018年的某一天，少女们和另一个世界的“自己”相遇了——。 高中生土宫明日架与朋友们隶属“矿石电台研究会”，在一次游戏中，她们效仿都市传说举行了“某个仪式”。不料仪式打开了平行世界，她们踏入了与日常截然不同的领域，新世界的大门就此打开。

Gu Xiaojiao, a young girl from 2018 and Lu Ming, a man from 1999, discover that they have both woken up in the same bed at the same space-time. More surprisingly, they realize that they can time travel by exiting the bedroom door. The fun begins when they start to plan a number of changes within these two eras. However, they do not know that their destiny is in the hands of a mysterious person.