Provoked by the full moon for hundreds of thousands of years, migratory crabs on the Australian territory of Christmas Island travel in their millions from the jungle towards the ocean. Every day, Poh Lin Lee, a trauma therapist, talks with the asylum seekers held indefinitely in a high-security detention centre hidden in the island’s core. The local islanders carry out their “hungry ghost” rituals for the spirits of those who died on the island without a burial.