Spear-wielding bodyguard Balsa is hired to protect young Prince Chagum after a water spirit's egg is implanted in him, a burden that marks him for death by his own father's order and draws pursuit from creatures of the parallel realm of Nayugu. Balsa is bound by a private vow to save eight lives, one for each of the eight taken years earlier to keep her alive as a child, and she smuggles Chagum out of the palace and into hiding. This manga adapts the first Moribito novel.