The story of Sekachu begins with Renri Ōmi's younger sister Kokoro being discharged from the hospital.

Much of its gameplay is spent reading the text that appears on the screen, which represents the story's narrative and dialogue.

Throughout the game, the player encounters CG artwork at certain points in the story, which take the place of the background art and character sprites.

[1] There are four main plot lines (and a bonus route) that the player will have the chance to experience, one for each of the heroines in the story.

Throughout gameplay, the player is given multiple options to choose from, and text progression pauses at these points until a choice is made.

[6] The game was originally going to be called Tobira no Mukō no Sphere (扉の向こうのスフィア), but in mid-development, Celery and Tetsujin wanted to change the title, and searched in bookstores for inspiration.

[6] Celery directed the game, and wrote the scenario; Tetsujin and Tamaki Ichikawa also contributed to the writing.

The game was postponed for a month, before being released as a limited edition DVD-ROM for Windows PCs on January 31, 2014.

[12] A full version of the game was put up for download on the official website - this time, not for free - on October 2, 2015.

[13] Before the game's release, Sekachu received a fair amount of publicity in bishōjo magazines such as Tech Gian, Dengeki Hime, BugBug, Push!

1 in the January 2014 sales ranking on Getchu.com, a major redistributor of visual novel and domestic anime products.

[19] Sekachu is part of Bushiroad's Chaos TCG trading card game series, and has been released as a booster pack.