Jin Tian, a young woman who recently got dumped by her fiance and lost her grandmother, Chen Lanxin. Feeling heartbroken, she travels to Prague, the place where her grandmother once spent years of her life. In her grandmother's belongings she finds a letter from 1970. In Prague, Jin Tian meets Peng Zeyang, a young single father who lives with his daughter and mother. The two develop a mutual attraction during their journey on searching Josef Novak, her grandmother's past lover.

An exploratory dive into the deepest depths of the ocean of a daring research team spirals into chaos when a malevolent mining operation threatens their mission and forces them into a high-stakes battle for survival.