Edit: The backstory of Sprig and Polly's parents is different from the show, but the one part I wanted consistent was that Hop Pop didn't know about Andrias being evil.
"Hi, Sprig...Polly..."
Sprig and Polly were in utter disbelief. Not only was their mom still alive, but she's been in the human world this whole time. Sprig took a step back.
"I don't understand...I...I thought you were..."
"Dead? I am so sorry...but...I had no real choice in the matter..."
"No real choice? You abandoned us! You could've taken us with you! How...how could you do this to us?!"
"Sprig, please, you don't understand!"
Sprig began yelling louder. "Oh, I understand well enough! You didn't want us! You could've taken us with you, but you left us and you gave the box to Hattie! What, were you not intending on coming back?!"
Helena looked down. Her silence was enough of an answer as far as Sprig was concerned.
"Helena, please..." Hop Pop walked over to Helena and touched her shoulders. "They deserve to know what really happened that night..."
Polly glared at Hop Pop. "You...knew? All this time, you knew what happened to mom?!"
"I'm sorry kids...I..."
"What the heck?!" Sprig could feel the anger pulsating within. "You promised there'd be no more secrets! And now me and Polly are just finding out our mom is alive, and you knew this whole time?!"
"Sprig please, if you'd just let us explain..."
Sprig, in tears and utterly heartbroken and angry, ran off back in the direction they came from, into the swamp. He wanted to be anywhere else but there.
"Sprig, wait!" Anne ran off after Sprig with Polly in her hands. Anne moved as fast as she could through the swamp, tracking Sprig's footprints. Dang it, Sprig, you move so fast!
After about ten minutes of tracking, Anne was finally able to find Sprig. He was sitting on a boulder, silently crying to himself.
"Hey, Sprig...can I sit by you?"
Sprig nodded and Anne took a seat by him.
"I can't believe this...I can't believe Hop Pop lied to me all this time...and Polly..."
Anne held onto Sprig. "I'm so sorry, Sprig..."
"And what about dad? Is...is he here too? I have so many questions, and...I don't know what to believe anymore..."
Anne could feel her heart tear in half. She couldn't think of anything to say. She held Sprig tighter as he cried loudly into her shoulder. Polly started to feel the tears flow as well, and she hugged her older brother.
The others soon caught up with them. Hop Pop put his hand on Helena's shoulder.
"Helena...you owe them an explanation."
"I know, dad..."
Helena walked over to Sprig, Polly, and Anne. Sprig looked over at his mom, then looked away. Helena had a look of shame on her face.
"Sprig...Polly...I..."
"Save it..." Sprig started to walk away.
"Wait, I...regret what happened...I really do...I spent every day for the last 5 years regretting what I did..."
Sprig stopped and turned around. "Then why did you do it?"
Helena sat down and started to explain what happened. Sprig's memory of that night had been repressed, but as Helena told him what happened, he began to have recollections...
5 years earlier...
Helena layed a newly hatched Polly to sleep and she went back out into the living room with her husband. Hop Pop came to visit Sprig and meet Polly for the first time. They stepped outside to talk while Sprig and Polly were asleep. Helena felt the cool breeze of autumn on her face as she conversed with her husband and father about their plans for the future.
Then, as they were about to go back inside for the night, they heard a sound. They turned around to find that the toads were there. Unsure of what they wanted this time of the night, her husband walked up to the toads while the others hid in the house.
The leader of the toads spoke. "We're here on behalf of King Andrias. We have word that there's something here that he wants."
"What would King Andrias possibly want from us? We're just farmers."
"Have you by any chance seen a box with three gems on it?"
They know about the box? "Uh, I can't say I have...why does he need this box?"
"For reasons that only King Andrias knows...we'll need to search your house just in case."
"Hey, wait, this is an invasion of our privacy! Unless you have an actual reason to..."
"Step aside..." the toad pushed him out of the way, but he got back up and stood his ground.
"You're not gonna push us around!"
The toad pulled out his blade. "I told you to step aside! Don't make me skewer you, little frog!"
The toad pushed by him again and busted open the door. The toad then felt a sharp pain in his back as a dagger punctured it. He shook off the frog and he hit the wall behind him. The toad towered over the frog and, in a fury, slashed him in the chest.
"You brought this on yourself..."
Helena heard a sound and looked out the window and saw her husband dead on the ground. Helena then grabbed the children and ran out the back with Hop Pop. Helena took a bag which had the box in it.
"What's going on, Helena?" Hop Pop asked.
"Dad, take the kids away from here! I'm gonna bring the box somewhere that it will never be found!
"Where are you taking it?"
"The box can send me into the human world! From there, I can hide it...they won't be able to get their hands on it if it's in the human world..."
"But, is there enough charge for you to get back?"
Helena paused, and looked over at Hop Pop with tears in her eyes. "I don't know...if I don't come back, please take care of the kids..."
Helena opened the portal. She looked back on her family one last time, and then turned to walk through the portal. Helena then felt a sharp pain in her back. An arrow hit her just as the portal was closing, to the shock of Hop Pop and the children. The portal then closed up, and Hop Pop, in tears, ran into the woods with the children.
"Dammit, the box is gone...King Andrias is gonna have my head..."
Helena found herself waking up hours later in an unfamiliar setting. There was an odd looking light on the ceiling, and a strange creature in the middle of the room.
"W...where am I? Did I...make it into the human world?"
"You were badly hurt, so I fixed you up...I'm Hattie, by the way...I'm surprised you can talk though...you were murmuring about a box..."
"Oh yea, the box!" Helena saw her bag on the side of the bed and grabbed the box out of it. She opened it, and...
...nothing...the box didn't work...