Tamsin Thomas is the Last Pellar, destined to keep humanity safe from magical forces. When Tamsin's class visits a disused old mine, Tamsin soon realises that there are mysterious creatures hiding underground. But something else stirs deep beneath the earth . . . There's a dark, ancient evil down there, one that's been trapped for a very long time. Tamsin will need all her wits about her if she's going to confront it, and keep everyone she cares about safe . . .