A police chief who takes in a young child she finds near the site of a mysterious accident who has no memory of what has happened.

A mysterious illness takes hold of Piper, while Jo and Benny investigate a powerful tech mogul, Richard Kindred. As Piper’s health deteriorates, Jo weighs accepting help from an unknown source. Meanwhile, Alex works to decipher a radio frequency code from Piper’s plane crash, and Ed has a follow-up oncology appointment.

After learning more about Piper’s origins, Jo struggles with the decision to shelter her. Benny enlists a friend to hack Kindred’s secret files, and Chris clashes with a headstrong informant he’s assigned to protect.

Jo is determined to prove Kindred was behind the attack on Benny and April. Meanwhile, Piper experiences intense, confusing visions.

Jo and Benny investigate the death of Kindred’s former business partner. Meanwhile, Mia and Piper experiment with Piper’s powers, and Alex confronts Ed about his health.

Jo and Chris rush to find Piper before she’s put in harm’s way. Meanwhile, Jo faces new challenges at home after betraying Alex and Ed’s trust.

The FBI arrives in Southold, complicating Jo’s efforts to find Emily. Meanwhile, Alex and Piper hunt for answers on a road trip, and the family celebrates Mia’s birthday.

Jo and Chris must evade the FBI as they investigate an elusive group of cyber terrorists. Ed’s presented with a cancer treatment that seems too good to be true, and a mysterious woman’s attempt to reach Piper puts the entire Evans family in danger.

After months of dead ends, the Evans family receives information that could finally lead them to Piper; Ed helps Mia as she tries to send Piper a message; Alex and Chris stumble upon a mysterious shipment in the harbor.

Jo and Brooks assemble an unlikely team as they attempt to communicate with Piper. Meanwhile, Piper is intent on saving Benny from Helen’s mysterious mission, and Alex receives a life-changing offer.

Jo makes a high-stakes deal to take down Helen and keep Piper safe. Meanwhile, Helen attempts to replicate Piper’s powers for herself, and Benny struggles to earn back Jo’s trust before it’s too late.

In the season finale, Jo and Brooks are in danger, and Piper’s determined to help. With Helen’s mysterious plan nearly realized, Piper recruits an unexpected team of allies to find them before it’s too late.