Goddess of Victory Sea you Again Movie

An investigation of the strange signal detected near Blue Water Island initially finds nothing anomalous. That's all well and good, but for Helm, this is her first official mission, and her chance to see the ocean for herself. Amidst her anxieties to do well and socialize with the others, another, much larger signal is detected...
A sequel to the event Blue Water Island, the protagonist returns to the idyllic tropics in pursuit of a strange signal. However unbeknownst to them, this signal belongs to a giant Rapture that lurks in the depths.