THERE ARE NO DO-OVERS IN SPACE For Curtis Walker, being chief of security on Dark Landing means fighting boredom and feigning integrity. Caught in a quagmire he created, his greater struggle now is survival. That's an ambitious goal since he can't tell his friends from his enemies, and the evil alien blackmailing him can assume any form. Forced to team up with his reluctant assistant, the station's irksome new chief of administration, and the runaway...