Coast Guard team intercepts a mysterious blue boat that does not appear on their radar and has an unusual appearance. The team attempts to communicate with the person inside, but no response is given. They decide to investigate further by pulling the boat closer, but it turns out to be a submarine. The two Coast Guard members who enter the submarine are cut off from their team when the hatch closes and the submarine begins to submerge underwater. They try to communicate with their team but the signal is dead. The two men are left stranded in the submarine, unsure of its purpose or their next steps.
While waiting, they search the submarine for clues. They discover a heavy metal door on the other side, but are unable to open it. Suddenly, the submarine starts vibrating and rising to the surface. Once above water, they hide and observe as three shady individuals enter the locked compartment of the submarine, carrying large packages. The men are part of a criminal trafficking ring using the submarine to transport large quantities of illegal drugs from one place to another, with the oil rig platform acting as a central point for the operation. The Coast Guard members are stranded and can only observe the illegal activities.
They manage to contact their team and alert them to the situation, but discover that the submarine involved in the operation is being refilled with drugs. With only 30 minutes to act, they sneakily take over the main operating room of the rig and prevent the submarine from making another run. The criminal organization’s leader is caught off guard and is quickly arrested, along with his men. Brendan and John are hailed as heroes for making the biggest bust in their careers.