It is old home week at Freeform‘s new Dead of Summer TV series. The show, created by Lost vets/Once Upon a Time creators, Adam Horrowitz and Eddy Kitsis and Once producer Ian B. Goldberg, just cast Elizabeth Mitchell and Elizabeth Lail. The duo joins Zelda Williams, Mark Indelicato, Alberto Frezza, Eli Goree, Ronen Rubinstein, and Paulina Singer.

Mitchell, who has been cast as Dead of Summer‘s camp owner, Deb, played Juliet Burke on Lost. She also guest-starred on Once Upon a Time, opposite Lail’s Anna, during the fourth season’s Frozen arc. On Dead of Summer, Lail will play Amy, a clever but nervous newbie Camp Clearwater counselor.

Freeform says Dead of Summer is part coming-of-age story, part supernatural horror story which “examines the light and dark of a summer like no other.”

Here is the Freeform press release:

Elizabeth Mitchell and Elizabeth Lail Join Freeform’s Highly Anticipated New Original Series “Dead of Summer”

ELIZABETH MITCHELL AND ELIZABETH LAIL JOIN THE GROWING LIST OF

CAMP COUNSELORS IN FREEFORM’S HIGHLY ANTICIPATED

NEW ORIGINAL SERIES “DEAD OF SUMMER”

Freeform continues to pull up seats to the campfire with the additions of Elizabeth Mitchell (“Lost,” ”The Purge: Election Year”) and Elizabeth Lail (“Once Upon a Time”) to its new original series “Dead of Summer.” Mitchell joins already announced cast members Zelda Williams (“Teen Wolf”), Mark Indelicato (“Ugly Betty”), Alberto Frezza (“Charlie’s Angels”), Eli Goree (“The 100”), Ronen Rubinstein (“Orange Is the New Black”) and Paulina Singer (“Gotham”).

Set in the late 1980s, school is out for the summer and a sun-drenched season of firsts beckons the counselors at Camp Clearwater, a seemingly idyllic Midwestern summer camp, including first loves, first kisses—and first kills. Clearwater’s dark, ancient mythology awakens, and what was supposed to be a summer of fun soon turns into one of unforgettable scares and evil at every turn. Part coming-of-age story, part supernatural horror story, “Dead of Summer” is a bold, new series that mixes genres as it examines the light and dark of a summer like no other.  Production on the series will begin in March.

Mitchell will be playing “Deb,” the new owner of Camp Clearwater. Once a camper herself, Deb has her heart set on bringing back the magic of the summer camp she loved. She exudes authority while simultaneously presenting a warm and welcoming vibe. Behind closed doors however, Deb seems to value her control over the camp for a much darker reason.

Lail will be portraying “Amy,” a clever but nervous camp counselor who is new to Camp Clearwater. Amy is not unfamiliar with being the new girl in social situations and the pitfalls that come with it, so she tries hard to fit in with the already bonded counselors. As the others reminisce about their past summers at camp, Amy is the first to discover clues that something disturbing is going on at Camp Clearwater.

“Dead of Summer” will be produced by ABC Signature Studios and Kitsis/Horowitz. Adam Horowitz, Edward Kitsis (“Lost,” “Once Upon a Time”) and Ian Goldberg (“Once Upon a Time,” “Criminal Minds: Suspect Behavior”) will write and executive-produce the series. Horowitz and Kitsis will direct the first episode.

About Freeform

Part of the Disney|ABC Television Group, Freeform is distributed in 94 million homes. The network connects to audiences and goes beyond entertainment with bold original programming and immersive social engagement. The network delivers a unique mix of quality original and acquired series, plus fan favorite movies and the holiday events “13 Nights of Halloween” and “25 Days of Christmas.” The Freeform app is a service that allows viewers with participating TV subscription services access to 24/7 live viewing of the network, as well as continued on-demand access via a wide array of devices.

About ABC Studios

ABC Studios is a leader in the development, production and strategic distribution of entertainment content across broadcast, cable and on demand platforms. The studio is the key content provider for the ABC Entertainment Group, having produced multiple seasons of hit series, including current shows “American Crime,” “black-ish,” “Castle,” “Grey’s Anatomy,” “How to Get Away with Murder,” “Marvel’s Agent Carter,” “Marvel’s Agents of S.H.I.E.L.D.,” “Once Upon a Time,” “Scandal” and “Secrets and Lies” for ABC; “Criminal Minds” for CBS, “Devious Maids” for Lifetime, as well as past hits “Desperate Housewives,” “Lost” and “Revenge.” For the 2015-16 television season, ABC Studios is producing “The Muppets” and “Quantico” on ABC, “Grandfathered” on FOX and “Code Black” and “Criminal Minds: Beyond Borders” on CBS.

Established in 2013, ABC Signature is ABC Studios’ boutique division, which spearheads development in premium and basic cable, emerging platforms and off-cycle, direct to series programming for broadcast networks. Signature recently completed production on the multi-cam comedy pilot for Freeform entitled “Gorgeous Morons,” produced by Danny Chun, Lee Eisenberg and Gene Stupnitsky. ABC Signature’s series credits include the USA half-hour comedy “Benched,” starring Eliza Coupe, and the ABC drama series “Blood & Oil,” starring Don Johnson and Chace Crawford.

This is a good week for former Once Upon a Time guest stars. Elliot Knight, who played the sorcerer Merlin in the first half of season five, has just been cast in the American Gothic TV series, coming to CBS, this summer. Read more about it, here.

What do you think? Do you like the sound of the Dead of Summer TV show? How do you like the casting so far? Let us know, below.