Japanese Navy have selected their next Allied target to attack, in a bid to destroy the US Navy's Pacific Fleet: Midway, a tiny atoll near Hawaii.

Japanese Admiral Yamamoto hopes to create "second Pearl Harbor" by attacking Midway, luring out the American fleet, then destroying it with bombers & warships.

US cryptographers, codenamed MAGIC, are reading cracked Japanese codes- they predict an attack on Allied fleet at Midway, Hawaiian archipelago.

To confirm site of planned Japanese attack, US Navy intelligence secretly orders Midway base to radio that their water purifier has broken down. American cryptographers soon detect Japanese signal: "Target is short of water."