Everything you need to understand or teach Alien Citadel by Douglas Hill.
Alien Citadel is the final book in a trilogy that features the young hero Finn Ferral. Readers who have already encountered him in the two previous novels will be interested in learning whether the situations left unresolved will come to a happy ending for this brave young man. Even those readers unfamiliar with Finn's previous life, however, will have no trouble picking up on the history of events in this novel. Enough background...