Synopsis for the English edition:
"Ever since his young son drowned to death, Ando has suffered recurrent nightmares. His wife has come unhinged after their devastating loss, which doesn't help. Work is his only salvation these days - and it's performing autopsies. But Ando's depressing world of routine and regrets is about to change when Ryuji Takayama, an old rival, appears before him as a corpse to be dissected.
Through Ryuji's bizarre demise, Ando learns of a series of mysterious deaths that seem to have been caused by an unknown - or rather, forgotten - virus. Behind it all lurks a suspicious videotape to which Ryuji seems to be leading Ando from beyond the grave. A choice more sinister than the one in Ring faces the doctor at the end of a breathless chase through places and minds.
Spiral is not only a sequel to Ring but also a commentary on it that breaks down the story and recasts it entirely. Spiral is written as a stand-alone work."