then throws him into a cell, not far from Poopsnagle himself. They do not know that they are so close to each other. The children suspect that the Doctor has been captured and enlist the help of the police to question Sator. Sator is very helpful and allows them to search the dungeons, but they do not find a thing. Poopsnagle has escaped once more and, as the door to allow the police to leave opens automatically, Poopsnagle takes his chance and runs out; but Sator soon recaptures the old man once more. The children mount a night raid on the castle to find Garcia, as they are convinced that he is in the dungeons. They find Garcia (but not Poopsnagle, as they do not realise that he is also in the dungeons), however Sator traps them in the tidal cell, where the tide will eventually drown them. Matt, however, has been following their movements and he is able to help the children escape from a high air grate. The Poopmobile is hovering overhead, and they scramble aboard with the help of the ladder. Sator is furious, but powerless to stop them. Once free, the Doctor and children fly to the island "which is joined by sand". This is part of the cryptogram, and they sight it from the air. When they land, they soon find the salamander and mineral with the help of a metal detector. Successful again, they head for home to decipher the next cryptogram. Part 5: Race to the finish The story begins with the children already on their way to their next destination. They have to find a bend in a river in the shape of an M. The River is in a northerly direction from their camp, and as they are flying, they see a bush fire in the distance and some people in distress. They land and rescue a man and a woman and some small animals. The woman is desperate for them to go after her daughter, who has left the farm in search of her horse Victory Stride. After dropping them off at the nearby town of Rivers Bend, the children search for Alice, the missing girl. They find her, and Carmen helps her by staying with her whilst the Poopmobile gives them directions from above. They escape the fire, and Sparks, back at Secret Valley, helps the situation by warning