From MangaHelpers: In 2019, childhood friends Yashio Kaito and Senomiya Akiho are in their last year of high school. Together, they are the only students in the robotics club, which has lost its school funding. Akiho is passionate about robots, and longs to complete building the robot her older sister Misaki began in this same club. Kaito doesn't really care about robots, and is obsessed with video games, specifically "Kill Ballad Online." However, he stays in the robotics club due to his friendship with Akiho. Now, just after Kaito is accused of cheating in his favorite game, Akiho decides to risk her club's existence in exchange for the funding to finally finish her sister's giant robot...
This is an original story expanded from the STEINS;GATE game, and focusing on the heroine Amane Suzuha. In 2036, a monopoly on time machines has created world peace, but at the cost of human liberty. Suzuha has followed in her late father's footsteps in fighting alongside the Valkyrie rebellion force to change the world. After the group fails on a major mission, Suzuha has almost no hope left. But then she discovers that her father left something for her: a time machine. Using this, maybe Suzuha will have the power to finally destroy this dystopian society and create a better present and future!
The story of Steins;Gate takes place in Akihabara and is about a group of friends who have managed to customize their microwave into a device that can send text messages to the past. As they perform different experiments, an organization named SERN who has been doing their own research on time travel tracks them down and now the characters have to find a way to avoid being captured by them.
From MangaHelpers: An alternate story of "Robotics Notes." In 2019, childhood friends Yashio Kaito and Senomiya Akiho are together in their high school's robotics club, but it is in danger of being abolished. Akiho wants to preserve the club, as she feels like it is her last link to her older sister, a roboticist. Akiho has only Kaito to rely on, but he's more interested in the game "Kill Ballad Online." It turns out, though, that Kaito's obsession with Kill Ballad may come in handy for their robotics club, and there are other allies they'll meet along the way! [tethysdust]