The in hiding challenge
This is the very first challenge I have written.
Story
Your sim loves to taake care of children toddlers to be exact. Your sim is so in love with taking care of children that they have 7 toddlers all adopted. See your sim has parinoid scitzifrenia (I probably spelled it incorrectly)and is afraid of the world around them and thinks that her doctor is out to get her for not taking her pills so afraid they do not even own a regular house they live in a basement. Your sim loves toddlers and children and even teenagers and they want the best for them. but how can the children be the best they can be if they cannot even be exposed to the outside world?
RULES
MUST HAVE one young adult man or woman
MUST have your sim start out with 7 toddlers
YOU CANNOT use the walker or playpen AT ALL (challenges are supposed to be hard!)
Your sim cannot talk to any other sim except for their children
Children cannot talk to anyone else except for each other and their parent
Children cannot clean they have to relax read or go on their phone all day
teens are not allowed to have a part time job
Children and teens are not allowed to go to school
NOBODY is allowed to go to university
Children CANNOT have afterschool activities
STEPS
1.Create your main sim and 7 toddlers
2.move them into an empty lot
3.build them a basement with a ladder or staircase and a room with no door or furniture above it
4.delete the school
5. HAVE FUN!!!
-5 points if anyone goes outside
+5 for each toddler you can choose a trait for
-5 each toddler you cannot choose a trait for
+5 for each child and teen who grows up in a good mood
-2 million each time a child teen or baby gets taken away

...The main character of the challenge is someone who is in love with children and keeps them in a basement? Do we need pedophilia mods for this?

Sorry about that here is more to the back story your sim has a mental disorder where they are afraid of everything so they gather up children but yeah its creepy really creepy

Yeah, you might want to edit the original post to reflect that tidbit, because Yeezus you can't just go around talking about "loving" underage children and not provide context.

This seems fun! I'll set up their basement so it's like Fallout, with the vaults. I have the homeschool mod, so they'll be doing that.
I agree with Mammal, you need a better backstory. Maybe, your character lives in a post-apocalyptic world, and he/she saved children and are going to be protecting and raising them. Like, training them in athletic, teaching them "life skills" (homeschooling) 'n stuff.