Disclaimer: I don't own Supernatural or Undertale. I'm just an obsessed fan of both.

Chapter 1

Dean's first thought upon waking up was, dad's gonna kill me.

The first words Dean spoke aloud were, "son of a bitch."

It was his fault, really, why they were in this mess.

John, as usual, had planted his two sons in a hotel for a few days while he ran off to hunt a monster. The town they were staying in was called Ebott after the mountain on which it resided on, and, according to legend, the place had always been shrouded in mystery. Reports of missing children and strange sounds had been all it took to rope the Winchesters into hiking all the way up the mountain to investigate.

"Best I can think of is a rawhead," John had warned gravely, head turned over his shoulder to look at his eldest son. "I want you two to stay here and out of trouble until I get back, okay?"

"When will you be back?" Dean had asked uneasily as John took another step out the door.

"I don't know; I'll call. You got food and stuff to keep you busy. I'm serious, don't leave this room." John made to swing the door shut behind him but hesitated. "And Dean... Take care of Sammy." With that, the door shut with an audible click.

"Where's dad going?" Sam asked, a grim sort of acceptance heavy in his voice. At almost eight years old, he'd just been introduced to the world of monsters, and was slowly adapting to the fact that that was where his father disappeared to whenever he left.

"Didn't say," Dean lied nonchalantly, flopping onto the couch beside his brother and picking up the remote. "TV?"

Sam had stared at him with those puppy dog brown eyes for a few seconds before giving in and nodding in agreement.

The rest of the day passed much the same, as did the day after, and the one after that. No, the real problem started almost a full week later.

"Dean?" Sam's sleepy voice drifted from the kitchen, and a few seconds later he and his Spiderman pajamas were padding into the living room, holding an empty half gallon of milk. "We're out of milk."

Dean glanced up from his position laying on the couch. "Do we need milk?"

"I want cereal," Sam protested, once again using the power of his puppy dog features for evil.

"Why don't you have toast?" Dean suggested.

"I don't want toast."

Dean let out a weary sigh and forced himself into a sitting position. Yes, John had told him not to leave the hotel, but it'd already almost been a week, and they were low on supplies. There couldn't be any harm in taking a quick trip to the grocery store, or even the gas station. Plus, staying cooped up in here with an energetic seven year old was slowly driving him insane.

"Alright. Get dressed, we'll go to the store."

Sam's entire face had lit up, and he quickly dashed to his suitcase to find clothes. Dean grinned slightly at his brother's enthusiasm- it was infectious. That being said, he still made sure to exaggerate every step it took him to get ready, just because he knew it'd annoy his little brother.

The town seemed nearly deserted. The houses were few and far between; rundown with almost no vehicles in any of their driveways. Even what little grass there was this far up the mountain seemed burnt and yellow and crunched under their feet. A single rusty car slowly ambled down the street; the driver glared at Dean as he drove past.

This unsettled Dean a little, but Sam was apparently unaware of the sensation of foreboding, and smiled widely as he breathed in the crisp mountain air.

They walked for a few minutes, Dean having no idea where the nearest convenience store was. Fortunately, Sam hadn't seemed to take notice, and helped calm Dean's nerves by continuing to chatter on excitedly about his favorite cartoons and books.

That was until his cheerful rambling broke off in a startled squeak as the thing grabbed him from behind.

Long story short, neither of them had had any weapons, and after wrestling Sam away from the monster (neither of them had gotten a good look at it, and Dean could only assume that it was a rawhead), all they could do was run. And, in doing so, trip into this crevasse and fall into this dark cave.

John was so going to kill him.

"Dean?" Sam questioned tentatively, snapping Dean's attention back to the present. He sounded scared, and Dean once again cursed himself for putting them in this predicament. "Where are we?"

"Couldn't tell ya," Dean replied a bit tersely, scrambling to his feet and squishing the bright yellow flowers beneath him. "but we gotta get back before dad does."

Sammy, still sitting on the suspicious patch of yellow flowers, tilted his head back and looked all the way up to the distant hole at the top of the cave. His face twisted into a confused frown and he swung his gaze back to his brother. "How?"

Dean sighed and looked around the cave. The only light came from the far-off mouth of the cave ceiling, casting everything but the flowers in a dull gray shadow. When Dean turned around, he could see that the cave stretched into a hallway-like corridor and end at what seemed like an intricately designed archway. As far as details went, there was nothing else of much interest down here.

Everything about this screamed danger to Dean. A pathway, underground? And these flowers... They couldn't have grown naturally, so someone had to have actually planted them there.

Someone had planted flowers deep inside a mountain.

Dean helped pull Sammy to his feet and gestured down the long hallway, feigning confidence and doing his best to take the scary out of this situation. "Let's explore a little. We're bound to find something."

He didn't mention the fact that that something probably wouldn't have good intentions, or that they didn't have any weapons, or that they didn't even have food or supplies to survive for however long it might take to get out.

At this point, Dean was thinking he might as well have tried to take on the rawhead.

Sammy nodded at Dean determinedly, and together they cautiously set off down the narrow corridor.