Moving into a shabby apartment, a saturnine girl with hidden secrets finds a notebook that allows her to communicate with another world. A thrilling adventure taking place across multiple timelines ensues. Two protagonists who trapped in their own dilemmas decide to collaborate, collect and analyze clues, reveal the hidden truth that history has neglected and help each other find the path to redemption.

Red Line is a story-driven horror game with moderate puzzles. Player can control two protagonists in two worlds to interact with different residents, investigate items, solve puzzles to unlock memories, and put clues together to reveal the truth of the past. By recreating certain moments spent in the apartment, resolve the regrets and obsessions of the characters, and help them embark on the next journey.

Story revolving around dual protagonists in different worlds is told from multiple views
Episodic narrative, with unique tragedies befalling the families behind each and every door
Seamless switching between investigation, chatting, and puzzle solving provides an utterly immersive detective experience
Stunning and picturesque in-game graphics imbue this pixel game with a dynamic visual style
Well-designed sound effects and BGM selections are the icing on the cake that give players a more terrifying atmosphere.