In January 2022, one of the most powerful volcanic eruptions in recorded history rocked the Pacific islands of Tonga, sending shockwaves around the world. Through first-person accounts of the disaster and eyewitness footage, experience the terrifying power of the eruption and the devastating tsunami that struck the shores of Tonga. Why was this eruption so big, how did it cause the tsunami, and could another disaster loom? NOVA investigates on "Hidden Volcano Abyss."

In the rural farm town of Appleton, Wisconsin, a harsh winter has set in and a rogue figure named Mitchell has returned to the town he once terrorized. Maddy Ballister lost her father at the hands of Mitchell and now she's ready to find him and settle the score.

A psychology professor begins a case study with three subjects who are suffering from sleep paralysis. As the study goes on, what is real and what is dream become mingled with violent consequences.