Hashiba Kyouya is a 28-year-old game developer. With his company going bankrupt, and him losing his job, he returns to his hometown. Looking at the success of creators of his age, he finds himself regretting his life decisions as he lay distressed on his bed. As Kyouya wakes up, he discovers that he has traveled ten years back to the time before he entered college. Will he be able to finally make things right? This is a story about a failed person who is given a second opportunity to follow his dreams.

Forming a party with one's mother in an online game seems not only unlikely but also uncomfortable to most teenage gamers. Unfortunately, Masato Oosuki finds himself in that exact scenario. After completing a seemingly meaningless survey, he is thrown into the world of a fantasy MMORPG—and his mother Mamako actually tagged along with him! On top of all of that, Mamako turns out to be an overpowered swordswoman, possessing the power of two-hit multi-target attacks! After minor tension between the two, they search for party members, meeting the merchant Porta and the sage Wise, starting their journey to clear the game. [Written by MAL Rewrite]

Far from the city's noise lies Torishirojima—a quaint and peaceful island where time seems to move slowly. Hairi Takahara, a young boy nursing a wounded heart, uses the recent death of his grandmother as a quiet reason to leave the city for a summer retreat to Torishirojima. Upon reaching the island, Hairi finds himself surrounded by a refreshing, laid-back atmosphere, a far cry from the hustle and bustle he is used to. After moving in with his aunt, Kyouko Misaki, he prepares to spend the summer helping her sort through a shed full of artifacts his grandmother collected over the years alongside his cousin, Umi Katou, who is staying with them. While adjusting to the island's slower pace, Hairi decides to spend his free time exploring. He soon meets the cheerful Tsumugi Wenders; the antisocial Shiroha Naruse; the wandering Kamome Kushima; and the sharp-tongued Ao Sorakado. Drawn into their lives and the island's subtle mysteries, Hairi is gradually swept up in a summer filled with fun, nostalgia, and life-changing moments that will stay with him forever.

The compilation film will recap the anime's 59 episodes from seasons one to three.