Freeform's Mermaid Thriller 'Siren' Premieres Tonight - Watch a Sneak Peek!

Freeform is celebrating International Mermaid Day with the two-hour premiere of Siren!

The series centers on Bristol Cove – a coastal town known for its legend of once being home to mermaids.

When the arrival of a mysterious girl proves this folklore all too true, the battle between man and sea takes a very vicious turn as these predatory beings return to reclaim their right to the ocean.

In the second hour, Ben and crew of The North Star uncover a device emitting a strange sound, all while Ryn finds shelter in the home of the local folklore expert.

Eline Powell, Alex Roe and more star in Siren, which premieres TONIGHT, starting @ 8PM ET/PT on Freeform.