 Kondoo Isamu the 3rd has hired Lupin and his companions to recover the legendary Golden Cannon, that s located on board a ship that was sunken by the Shogunate forces in the Tsugaru Strait. The cannon is worth 8,000,000,000 Yen in todays market. The challenge is that strong violent sea currents occur momentarily making it dangerous to retrieve the gold cannon. So how will Lupin be able to over come the sea currents, and who is this Okida character?