midnight
When shall we start for the island ? '' `` As soon as we 've had supper , and gagged the prisoners again . It wo n't do to let them have the chance of warning Sam . '' `` It ai n't likely he 'll get back before midnight . '' `` That 's true ; but in the meanwhile we have a good deal to do . The camp-fire must be lighted , to prevent him from being suspicious when he comes in sight of the island , and we need to look about a bit for a hiding-place . '' `` Have you made up your mind how we are to strike him ? ''