Salvors are men responsible for towing wrecked ships and handling the cargo. They are different from rescue teams as they usually ask for money before offering help. Nanba Rintarous father was the owner of such a company, but Rintarou really hated the way they operate and decided to work in a proper rescue team.
However, Rintarous father died right after Rintarou completed his training. In his will he asked Rintarou to take over his company. What is worse is he left his son a debt of 1.5 billion yen.