On a European metropolis on the near future, a gang robs a bank. They sneak away through the city sewers, to get lost forever in the dark with the loot. Only a mysterious little girl witnesses the bandit’s fate. Years later, word is out that some moles, sewer trash collectors, and kraken, underground police squads; are disappearing on strange circumstances. The city is experiencing strange seismic shocks. Tomi an alienated teenage mole, embarks, together with Fermin, his authoritarian and caring father, on a subterranean quest of the mythical lost bank robbery loot. They will have to deal with the Kraken, the other mole clans and face a humongous creature, nurtured by a blind, haunted girl.