Kursaal is a pleasure world, a huge theme park for the Cronus system -- or rather it will be if it isn't destroyed during construction. Eco-terrorists want the project halted to preserve vital archaeological sites -- areas containing the last remains of the long-dead Jax, an ancient wolf-like race, whose remains are buried beneath the big-business tourist attractions. Sam falls in with the environmentalists and finds her loyalties divided. Meanwhile, the Doctor's own investigations lead him to believe Jax are not extinct after all.