"Welcome to your new home, innocent one." Toriel smiled at Frisk as they proceeded into the ruins.
"Allow me to educate you in the operation of the ruins." Frisk watched as Toriel walke over to an arrangement of 6 stones. She stepped on four of the six, before going to a wall and pulling a lever. A door slid open behind her. She turned back to Frisk.
"The ruins are full of puzzles. One must solve a puzzle to move from room to room." Toriel led Frisk into the adjoining room. Here she spoke again.
"Before we can move on, you will need to trigger several switches." Toriel stood aside, a clear indication that Frisk was supposed to do the puzzle. He could see at one end of the room that a wall of spikes blocked the path forward. He took note of three switches of the wall. Two of them had arrows drawn, pointing right towards the levers. He walked over and pushed the two levers the arrows indicated to, and the spikes fell away.
"Splendid! I am proud of you, little one." Toriel spoke cheerily. Frisk said nothing, not wanting to mention that it was literally laid out what he had to do. As they moved on, Frisk began to notice eyes watching. Suddenly something leapt out at him. What seemed to be a frog of a strange sort landed in front of him. Toriel was quick to shoe it away. As they walked, Frisk listened as Toriel explained how monsters would appear frequently, and how to deal with such things.
The two continued for what seemed like hours for Frisk. In reality it had just been 20 minutes. After having given Frisk the tour, Toriel led him over to her home. Frisk smiled. The house was nice, tidy, clearly Toriel was a good caretaker.
"I have a surprise for you!" Toriel led him down a hallway off to the right.
"This is it. A room for your own. I hope you like it! Make yourself at home." Toriel went off to tend to what smelled like a butterscotch-cinnamon pie. Frisk sighed as he saw the bed. In his room. It had been a long day. He climbed in and laid back, falling fast asleep.
The sound of a door closing roused Frisk. He heard footsteps proceeding away. As he leaned over to get out of bed he saw a slice of the pie that had been baking earlier. He decided to leave it until morning. However before he got back in bed he paused. Frisk spotted a toy knife on the ground. It seemed harmless enough. He shrugged and stuffed it in his pocket. When he returned to his friends, he could show them what he had collected.