The idea of icebergs in the tropical waters of the Barrier Reef at first amuses the Minus Five team, but the situation becomes grim when the icebergs prove to be real and a threat to shipping. Captain Ted King asks the inventor of the icebergs on board the Endeavour to join the team.
| Name | Type | Role | |
|---|---|---|---|
| Joy Cavill | Writer | ||
| Ron Haddrick | Guest Star | Dr Sedgewick | |
| Peter Maxwell | Director |