Gorou Kusaka serves as one of three junior sailor trainees aboard the newly commissioned submarine 707 II under Captain Hayami. Alongside fellow inexperienced recruits Kenji Minahaya and Senta Umino, he joins the crew during its critical mission to combat the USR terrorist organization. His trainee duties include operating the helm during intense combat maneuvers and high-stakes underwater engagements against Admiral Red's forces. Gorou's physical appearance features a distinctive choker collar, a notable element of his character design.