태양속으로 4.0

Lieutenant senior Kang Seok-min(Kwon Sang-woo) joined the navy to follow in his dead father's footsteps, with the dream of becoming an admiral. At the hospital where Seok-min's sister, Soo-jin(Kim Jung-hwa), a young doctor who is still an intern, Seok-min runs into Hae-rin, a female doctor at the hospital. He tries to get close to Hye-rin(Myung Sae-bin) but she has shut others out since her boyfriend from college died. Hae-rin's senior from the medical school Seung-ha, who is also the son of the director of the hospital, has been in love with Hae-rin since the college days. However, he could only love her from afar since his friend confessed his love first. After the death of his friend, Seung-ha plays the role of a guardian for Hae-rin, but only to win her love. Seok-min's honest and yet impulsive behavior throws Hae-rin off. Nevertheless, ever since Seok-min gets involved in a critical situation on the naval base Hae-rin finds her heart drawn to Seok-min...