忘れないでおとなになっても is a cinematic adventure game developed by GAGEX Co.Ltd. It takes place in a nostalgic and beautiful town from the past, where players can relive the mysterious summer adventure of a young boy named Minato. The game is set in a small town called Kagami, and Minato visits this town with his mother and sister. He has a secret plan to find his father, who he believes can save his sick sister and his mother, who is struggling with loneliness and fate.

Minato finally discovers a clue left by his father, a mysterious notebook called the "Seven Mysteries Notebook." Guided by the notebook, Minato embarks on a challenging journey to a distant and treacherous world, the Kagami town of the past, where his parents met 33 years ago.

Will Minato be able to change his fate and reclaim his lost family in the past world? The main story of the game can be enjoyed for free until the end.