The opening of Submerged Youth is set on an island threatened with rising sea level and the shortage of land. With the island's impending doom, the authorities of the Island seek to reduce the population by eliminating those who are "ungrateful" of the land by banishing them into the sea. This story is about a young student named Vi who has been accused of participating in a riot and is thrown into the ocean. After being saved by a little boy named Yok, she discovers a group of surviving rebels who take refuge in The Lost Mahanakorn, a forgotten city under the sea.

Submerged Youth represents how the voices of the younger generations are suppressed by the inhumane authorities, abusive education system and the ultra-conservative nature of the culture. The definition of what counts as "ungrateful" is purposefully made unclear to highlight how laws are written so vaguely that the authorities can abuse their powers and bend the laws to terrorize their citizens as they please.