The Way Home finally gave us the story behind the opening sequence of the series! The season 1 finale revealed that it had been Kat running through the woods as men with guns and torches chased her calling her a witch. It was clear that she wasn't in her time, she was actually in 1814, but we didn't know why she was tearing through the trees desperately trying to get back to the pond. Now we do thanks to season 2 episode 6, "How to Save the Life."
In the previous episode, Kat had seen her brother for the first time in two decades. But he was immediately grabbed by who she was led to believe were British soldiers. However, they weren't. As episode 6 showed, they were actually Cyrus Goodwin's men who'd disguised themselves so as not to bring attention to the wealthy man's doings.
It turns out that Jacob skimmed off the top of a deal Cyrus and Thomas Coyle struck. He'd done so at Thomas' direction so he could earn passage back to Port Haven after delivering Cyrus' ship to the war effort in Upper Canada. Cyrus caught wind of what happened, but he thought Jacob had acted on his own. He also bares a grudge against Jacob because he's engaged to Susanna Augustine.
Susanna's father had approached Cyrus with a request that he take her hand in marriage. He'd despaired that his daughter was getting older and had yet to be married. When he died, Susanna broke off the engagement. In order for her not to incur the wrath of Cyrus, Jacob protected her by proposing. She admitted to Kat that theirs would be a marriage of convenience.
Having learned that Jacob was being held by Cyrus and not the British, Kat went digging in some of Jacob's old things after she saw a key with the Goodwin crest in one of his pictures. Armed with the means of rescuing her brother, she lept back to 1814 and devised a plan with Susanna and Thomas that involved using jimson weed mixed into the drinks Thomas would ply Cyrus' men with in order to knock them out.
Susanna would act as a distraction, keeping Cyrus occupied while Kat, in a long wig and white dress similar to Susanna's, explored the tunnels under his home in search of Jacob. As Susanna had warned, jimson weed wouldn't be reliable when it came to keeping the men under long enough to sneak around, rescue Jacob, and beat a swift retreat. It really depended on a person's size and weight.
Cyrus Goodwin gave Kat Landry the name 'white witch'
Cyrus, who wasn't supposed to drink anything, wound up doing so when he took the cup of the man who brought Susanna to him. He woke up disoriented and was loudly looking for her in his drugged state. He found her in the tunnels, unbeknownst to him she'd knocked out one of his henchman who'd found Kat. Using their likeliness to their favor, the two made Thomas believe he was seeing double. They ran around and disappeared, calling his name as they did, giving the impression they were everywhere and nowhere at once.
He screamed that whoever was before him was a witch and then they appeared to vanish. Cyrus had simply had his eyes shut for too long but he was under the influence so their trick worked. Unfortunately, it didn't work well enough to buy them enough time to get Jacob out with all three of them together. Kat was able to locate him, and she used the key he'd found as a boy to do it. But Jacob had been whipped. Based on the sweat covering his body and the fact that he didn't wake up at all when he was touched or being spoken to, fever had set in.
Kat convinced Thomas and Susanna to let her be the one to lead Cyrus and his men off their scent. That way neither of them would be implicated, and they could get Jacob out of there. She stood before an open flame in front of his house and let him leap to the conclusion that she was a witch who'd stolen Susanna's face and deceived him. He called for his men to hunt her and hunt they did, through the Port Haven woods.
Thomas made sure Kat didn't get shot and she was able to make the jump into the pond unscathed after promising that she'd be back for her brother. When we first started this journey with The Way Home no one could have guessed that this would be how the white witch came to be a part of the town's folkore, but it's certainly a wild tale!