20 years ago a teenage boy discovered a 400-year-old bronze cannon in water close to the south Devon coast. Nobody has yet identified the ship it belonged to. As usual, Time Team have only three days to figure out who it belonged to. Tony is looking forward to getting into his diving suit but the team cannot dive until the wreck's archaeological supervisor arrives. Meanwhile the wreck's finder, Simon Burton, tells his story. Undeterred by disappointing geophysics results, the divers go ahead with their search in murky water.