Professor David Ullman's expertise in the literature of the demonic - notably Milton's Paradise Lost - has won him wide acclaim. But David is not a believer. One afternoon he receives a visitor at his campus office, a strikingly thin woman who offers him an invitation: travel to Venice, Italy, witness a "phenomenon", and offer his professional opinion, in return for an extravagant sum of money. Needing a fresh start, David accepts and heads to Italy with his beloved 12-year-old daughter, Tess. What happens in Venice will send David on an unimaginable journey from skeptic to true believer....

Episode Thirteen takes them to every ghost hunter's holy grail: the Paranormal Research Foundation. This brooding, derelict mansion holds secrets and clues about bizarre experiments that took place there in the 1970s. It's also famously haunted, and the team hopes their scientific techniques and high tech gear will prove it. But as the house begins to reveal itself to them, proof of an afterlife might not be everything Matt dreamed of.

Claire Kovalik is days away from being unemployed—made obsolete—when her beacon repair crew picks up a strange distress signal. With nothing to lose and no desire to return to Earth, Claire and her team decide to investigate.

Lifestyle journalist Katrine escaped past traumas by moving to a coast renowned for seaside holidays and natural beauty. But when a vast hoard of human remains and prehistoric artifacts is discovered in nearby Brickburgh, a hideous shadow engulfs her life. Helene, a disillusioned lone parent, lost her brother, Lincoln, six years ago. Disturbing subterranean noises he recorded prior to vanishing, draw her to Brickburgh's caves. A site where early humans butchered each other across 60,000 years. Upon the walls, images of their nameless gods remain.

Money's tight and their new home is a fixer-upper. Deep in rural South West England, with an ancient wood at the foot of the garden, Tom and his family are miles from anywhere and anyone familiar. His wife, Fiona, was never convinced that buying the money-pit at auction was a good idea. Not least because the previous owner committed suicide. Though no one can explain why.

It’s the house of their dreams. Former marine Harry and his wife, Sasha, have packed up their life and their golden retriever, Dash, and fled the corporate rat race to live off the land in rural Idaho. Their breathtaking new home sits on more than forty acres of meadow, aspen trees, and pine forest in the Teton Valley. Even if their friends and family think it’s a strange choice for an up-and-coming pair of urban professionals, Harry and Sasha couldn’t be happier about the future they’re building, all by their lonesome.

In a boarded-up house on a dead-end street at the edge of the wild Washington woods lives a family of three. A teenage girl who isn’t allowed outside, not after last time. A man who drinks alone in front of his TV, trying to ignore the gaps in his memory. And a house cat who loves napping and reading the Bible. An unspeakable secret binds them together, but when a new neighbor moves in next door, what is buried out among the birch trees may come back to haunt them all.

Ana and Reid needed a lucky break. The horrifically complicated birth of their first child has left Ana paralyzed, bitter, and struggling: with mobility, with her relationship with Reid, with resentment for her baby. That's about to change with the words any New Yorker would love to hear—affordable housing lottery. They've won an apartment in the Deptford, one of Manhattan's most revered buildings. Reid dismisses disturbing events and Ana’s deep unease and paranoia as the price of living in New York—people are odd—but he can't explain the needle-like bite marks on the baby.

Travel journalist and mountaineer Nick Grevers awakes from a coma to find that his climbing buddy, Augustin, is missing and presumed dead. Nick’s own injuries are as extensive as they are horrifying. His face wrapped in bandages and unable to speak, Nick claims amnesia - but he remembers everything. He remembers how he and Augustin were mysteriously drawn to the Maudit, a remote and scarcely documented peak in the Swiss Alps. He remembers how the slopes of Maudit were eerily quiet, and how, when they entered its valley, they got the ominous sense that they were not alone.

The challenge: Spend a week hiding in an abandoned amusement park and don’t get caught. The prize: enough money to change everything. Even though everyone is desperate to win—to seize a dream future or escape a haunting past—Mack is sure she can beat her competitors. All she has to do is hide, and she’s an expert at that. It’s the reason she’s alive and her family isn’t.

Long ago, Nathan lived in a house in the country with his abusive father—and has never told his family what happened there. Long ago, Maddie was a little girl making dolls in her bedroom when she saw something she shouldn’t have—and is trying to remember that lost trauma by making haunting sculptures. Long ago, something sinister walked in the mountains and the coal mines of their hometown in rural Pennsylvania. Now, Nate and Maddie Graves are married, and they have moved back to their hometown with their son, Oliver. And now what happened long ago is happening again...to Oliver.

Recently laid-off from his newspaper and desperate for work, war correspondent Nick Bishop takes a humbling job: writing a profile of a new mindfulness app called Clarity. It’s easy money, and a chance to return to his hometown for the first time in years. The app itself seems like a retread of old ideas — relaxing white noise and guided meditations. But then there are the “Sleep Songs.” A woman’s hauntingly beautiful voice sings a ballad that is anything but soothing — it’s disturbing, and more of a warning than a relaxation — but it works.

For nearly two decades, Jamie Warren has been running from darkness. He's haunted by a traumatic childhood and the guilt at having disappeared from his disabled brother's life. But then a series of unusual events reunites him with his estranged brother and their childhood friends, and none of them can deny the sense of fate that has seemingly drawn them back together. Nor can they deny the memories of that summer, so long ago—the strange magic taught to them by an even stranger man, and the terrible act that has followed them all into adulthood.

During the overthrow of the Mexican government, Beatriz’s father was executed and her home destroyed. When handsome Don Rodolfo Solórzano proposes, Beatriz ignores the rumors surrounding his first wife’s sudden demise, choosing instead to seize the security that his estate in the countryside provides. She will have her own home again, no matter the cost. But Hacienda San Isidro is not the sanctuary she imagined. Something is wrong with the hacienda. And no one there will save her. Far from a refuge, San Isidro may be Beatriz’s doom.

In an isolated chateau, as far north as north goes, the baron’s doctor has died. The doctor’s replacement has a mystery to solve: discovering how the Institute lost track of one of its many bodies. For hundreds of years the Interprovincial Medical Institute has grown by taking root in young minds and shaping them into doctors, replacing every human practitioner of medicine. The Institute is here to help humanity, to cure and to cut, to cradle and protect the species from the apocalyptic horrors their ancestors unleashed.