On the silent streets of Prague, all manner of mysterious creatures lurk in the shadows . The unsuspecting citizens' only hope against this horde of predators are the Lights, the secret monster hunters who, lighting Prague's gas street lamps every night , patrol the streets and keep the impending darkness at bay. Their existence, as Domek Myska knows well, is punctuated by constant clashes with creatures like the pijavice, soulless beings who are perpetually bloodthirsty. Nonetheless, Domek finds comfort in the moments spent in the company of his intelligent and charming friend Lady Ora Fischerová, a widow who hides many secrets of her own.

As if that wasn't enough, Domek finds himself haunted by the spirit of the White Lady, a ghost that haunts the baroque halls of Prague Castle, and comes across the sentient essence of a will-o'-the-wisp locked in a mysterious container. Young Luce discovers that she can harness its powers, but the creature, well known for luring unsuspecting travelers to their deaths, will not be easily controlled.