Profound grief and ominous visions of a river of blood spur ThunderClan cat Ivypool and four companions to undertake a dangerous questIn an episode punctuated by disturbing dreams and visions, Ivypool, who's caught between hope and despair after the recent loss of Bristlefrost, her kit, leads a multi-Clan expedition into unknown lands. They face battles with weasels and foxes, encounters with wildcats both friendly and hostile, and probes into the diverse realms of the afterlife. Lighter moments, such as one cat giving another dating advice or a glimpse of a Twoleg eating something inscrutable ("two white things, Ivypool realized, with something colored brown and yellow between them. He put the whole thing into his mouth and took a bite"), occasionally relieve the overall heaviness of the story's tone. By the quest's end, not only has Ivypool at last moved past denial to acceptance, but the expedition has made a remarkable discovery. What the collective author doesn't do here is offer even a hint of what that river of blood actually portends for the Clans beyond some vague, fearful threat-curious readers will have to stay tuned.A setup volume, ending abruptly in midcourse with dangers aplenty faced and more, plainly, to come. (Clan membership list, map)(Animal fantasy. 9-12)