The story takes place after Rintaro Okabe fails to save Kurisu Makise in the original Steins;Gate series. After failing to save Kurisu Makise in order to prevent a future war over time machines, Rintaro Okabe, traumatized over his experiences of meddling with the past with his Reading Steiner ability, chose to live in the beta world line where Kurisu stays dead. After several months have passed, Rintaro meets Maho Hiyajo and Alexis Leskinen, two of Kurisu's former colleagues who have been working on Amadeus, an artificial intelligence system using Kurisu's memories from before her death. Rintaro accepts a request to help out with Amadeus' development by becoming a tester, conversing with the Amadeus Kurisu through his phone.