In the midst of the Clone Wars, Master Mace Windu returns to his Separatist-occupied homeworld, where his former Padawan, Depa Billaba, has been working as an undercover agent. But Depa hasn't been reporting in lately, and Republic intelligence has been gathering disturbing hints of bloody ambushes and terror-strikes in the deep outback. Mace trained Depa--he knows that no one but he can hope to even reach her, let alone save her from the darkness.