The Baltic Sea Divers crew works aboard the barge BT2 to lay a 600-meter protective pipe beneath the seabed, using Horizontal Directional Drilling to bore a channel under the sea floor rather than trenching across it. The film follows the crew through the stages of the job, from positioning the barge and drilling the pilot bore to threading the pipe through and checking the installation, with underwater camera work showing divers working in near-zero visibility and heavy currents. Engineers and crew explain why HDD is used in this setting, what can go wrong when drilling blind through unknown seabed conditions, and how the barge and drilling rig stay coordinated with the divers below. The result is a plain, procedural look at a kind of offshore construction that rarely gets filmed, focused on the mechanics of the technique and the physical difficulty of doing precision engineering underwater rather than on personalities or drama.