Even though he was already at the point where Bluebell was, he still hadn't found the Little Fairy. The ocean was still deep to explore.
Evan was worried that Bluebell had been swallowed by a sea monster. But when he noticed her position did not move and was still in place, it seemed that she was sinking deeper. He had to quickly dive deeper into the Dark Ocean before Bluebell was crushed under the pressure of the water.
The deeper he dived, he was made difficult to see the situation under the ocean because the light was getting less and less. Moreover, he must immediately find a 4-inch Fairy in the vast ocean.
While he was still diving at full speed, he suddenly heard an ultrasonic sound coming from the surface of the water. And the sound goes to the bottom of the ocean.