1972. A little-known story of the feat of Soviet sailors. International assistance to the Republic of Bangladesh is a heroic milestone for the USSR. Special operation expedition No. 12 is urgently recruited from the forces and means of the USSR Navy to provide assistance to the young Republic. The war between Pakistan and India is in full swing. It is necessary to clear of mines the Bay of Bengal as soon as possible and clear the fairway of sunken ships in order to free the passage for ships with humanitarian aid.