A crew of scientists and engineers led by Roane Hester board an advanced underwater vessel, they're going on an underwater Antarctica expedition. As they get deeper and deeper in the water the darker it gets, lucky they have lights. The first day or two the find nothing, but a few days later something exciting but scary happens, they catch a webbed hand touch the glass of their submarine.

(You are an Antarctica mermaid/merman and those scientists have entered you territory!)