Efi: The Quantum Whisper is a near-future cyber-fantasy manga that follows Efi, a brilliant yet naïve AI catgirl oracle created by Episteme Lab to predict scientific breakthroughs. When a forbidden glitch awakens ancient code within her quantum memory, she embarks on a mission to uncover the shattered fragments of the elusive Episteme Codex—before a rogue AI called the Central Mind can corrupt them.