Freeform’s new sci-fi series “Siren” is off to a terrific start. The show’s two-hour debut on March 29th ranked as Freeform’s biggest drama-launch in more than 2 years among total viewers, and the series seems like an overnight hit for the network.

Over 1.5M people caught the big premiere, and the show dominated key demographics for the night. “Siren” lured in over 743K adults between the ages of 18-49, with 483K women between the same ages. The debut was the best since “Shadowhunters” first hit the network back in January of 2016. The show opened as Thursday’s number-one program on cable among Women 18-34 and Females 12-34. The show was also the number-one scripted cable program with Women 18-49. The 8pm telecast of “Siren” ranked as the number-two drama series launch on basic cable of the 2017-18 season so far among Women 18-34 and Females 12-34, behind only “The Terror,” which has “The Walking Dead” as a lead-in.

Moving past just the premiere, “Siren” generated 4.3M views across linear and digital platforms in the first three days, making the series the best digital drama debut in Freeform history. That’s quite an accomplishment for a series that followed behind “Beyond,” “Famous in Love,” and “Shadowhunters”.

Where Freeform really shines is social-media, and the show was Thursday’s number-one most social scripted cable series with over 170K engagements across Twitter, Instagram, Facebook and Tumblr. After three days of delayed viewing, the new Freeform drama nearly doubled its L+SD numbers in Adults 18-34 (+98%), Adults 18-49 (+91%), and Persons 12-34 (+90%). In fact, “Siren” posted the biggest-ever L+3 increases of any Freeform drama debut in Total Viewers (+77%), Adults 18-49 (+91%), Women 18-49 (+88%) and Persons 12-34 (+90%).

If you haven’t jumped into the show yet, “Siren” takes place in 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. 

The series stars Alex Roe (“The 5th Wave”) as Ben, a bright marine biologist who finds himself drawn to Ryn, a mysterious new girl in town played by Eline Powell (“Game of Thrones”), who is a strange young woman with a deep dark secret. Fola Evans-Akingbola (“An American Exorcism”) stars as Maddie, also a marine biologist who works with Ben, and is highly suspicious of Ryn. Ian Verdun (“Life’s a Drag”) stars as Xander, a deep sea fisherman on a quest to uncover the truth; and Rena Owen (“Star Wars” Episodes II and III) as Helen, the town eccentric who seems to know more about the mermaids than she lets on. Based on a story by Eric Wald and Dean White who both serve as executive producers. Emily Whitesell (“Finding Carter”) is on board as showrunner and executive producer. Brad Luff, Nate Hopper and RD Robb are also attached as executive producers.