The date is November 1964.
In this scenario, the Royal Navy submarine HMS Alliance is tasked with landing a No.2 Special Boat Section naval gunnery spotter team on the south west coast of Sebatik Island, so that they can identify Indonesian military targets for a punitive naval bombardment. The mission is using the cover of darkness on a moon less night in order to avoid visual detection.
The team must be dropped off shore at night, using a radical new technique for underwater insertion code named Goldfish. The submarine will not need to surface whilst the SBS team swims ashore from the submarine underwater, but it must remain undetected for the entire mission. It is expected that Indonesian naval units will be conducting routine patrols in the area and will probably have to be avoided.
At the start of the scenario, the Indonesian Riga class frigate KRI Jos Soedarso is positioned at the centre of the table, initially deployed as a contact marker. She is conducting active sonar and active radar sweeps. Her rules of engagement are to detect and destroy any enemy submarines or surface warships if encountered, with no other Indonesian naval units in the area. She may patrol in any direction but may not leave the map. The sea state is calm and nighttime visibility rules apply.
HMS Alliance is not deployed at the start of the game but is represented by ten numbered contact markers, which may be placed anywhere on the map, including at least one in the deployment zone and at least one in the SBS drop zone. Each marker must be at least 12cm from the next marker with a maximum of 30cm between each marker. They must be at least 12cm from any enemy contact marker. They must also be placed no closer than 12cm from the shoreline, as the SBS will be dropped off shore to swim underwater to the beach.
The contact markers act as stepping stones. In the first turn the position of HMS Alliance, which must be within the submarine deployment zone at deep depth, is recorded by the Royal Navy player in secret. In subsequent turns, the submarine's position may be shifted to any adjacent contact marker, adjusting the depth as required. The submarines actual position will only be revealed if she surfaces, fires a torpedo, operates in active sonar mode or is detected. HMS Alliance is operating in passive sonar mode to avoid detection. The rules of engagement state she may only attack if she has been actively detected and fired upon by the enemy.
If detected, all of the contact markers are removed and the submarine model is placed in position on the table. The frigate can attempt to eliminate dummy contact markers using active sonar detection and thus locate the actual position of HMS Alliance or force her to reveal her position by removing adjacent 'stepping stones'. This will prevent the submarine from moving from one marker to another, forcing her to deploy as a model. However, she will need to be detected before any attack is carried out.
To win a major victory, HMS Alliance must drop off the SBS team, taking one whole turn stationary at shallow depth to do so, then successfully exit via the opposite table edge. A minor victory will result if the team is dropped off but the submarine is subsequently detected yet exits the table undamaged or with only light damage. If HMS Alliance fails to drop off the team and is detected before she can do so, it will be a minor defeat. A major defeat will result if, in addition, the submarine is heavily damaged or sunk.