Hello guys! :D This is my first fanfiction, so please be gentle. Criticism is welcome! I apologize for any out of character-ness, I tried my best.
Little Sherlock is five in this one and Mycroft is twelve (Mycroft is seven years older than Sherlock in the original stories)
Regarding Mycroft's and Sherlock's nicknames, I assume Sherlock would call him 'My', I got 'Mykee' and 'Sherly' from the Guy Ritchie films
Lighting lit the sky up and thunder clapped. The wind was howling and every tree on the Holmes' manor was swaying dangerously. There was another flash of light followed by a loud boom. Little Sherlock shivered in the dark under his covers. Storms have always scared him and tonight it was particularly bad—even his nightlight offered no comfort. He could feel the tears welling up in his eyes. He flicked on his bedside table lamp and slipped into his dressing gown. Sherlock reached for his wooden pirate sword on the floor and crept out of his room.
The house was cold and silent. Mummy and daddy were away in London for the weekend doing business. The floor creaked under Sherlock as he padded down the empty corridor.
'Why is Mycroft's room so far from mine?' He groaned silently.
Clutching his sword, He pushed open Mycroft's door.
"My?" He whispered, fingers still holding on to the knob.
"Mykee?" Sherlock tried again, his voice shaky.
A soft groan came from under the covers. Lighting stuck followed by thunder and Sherlock yelped. He quickly shut Mycroft's door and scampered over to Mycroft. He pulled at his brother's covers and Mycroft cracked an eye open to see a teary eyed Sherlock.
"Mmmmm…? Sherly? What's wrong?"
"Mykee, I'm scared. Please, My, can I sleep here tonight?" Sherlock pleaded between his quiet sobs.
Mycroft shifted over and Sherlock placed his sword on the ground. He wouldn't need it anymore since Mycroft was with him. He crawled into bed and snuggled into the covers— it was warm. His breathing slowed down and he was calm again.
"Thanks for protecting me, My" he mumbled.
"I'll always protect you" Mycroft whispered as he drifted back to sleep.