Synopsis

Mega Marine Action!!

World's Strongest SSU - 187 meters deep,

Begins the Operation with risk of life

SSU's two divers, Jun and Taehyun, who are well known for their best skills, are best friends and rivals.

One day, Major Kang Soo-jin, the leader of SSU's training, appeared in front of them. Returning from studying abroad, she is an SSU motivation between Jun and Taehyun and ex-girlfriend of Jun.

After three years, they meet again with a different positioned. They are confused with friendships as precious as their lives and feelings that cannot be seen.

 

Finally, the naval joint training mink operation, the biggest operation of the SSU unit, will begin. However, during the operation, a large-scale accident occurred when a Korean Peninsula ship made an emergency landing in the deep sea, and Sujin, who was trying to rescue the survivors, was trapped in a sunken submarine. Jun and Tae-hyun jump into the 187-meter deep sea that no one has ever tried to save Su-jin...