Sigma and Nikolai

Your mother had to travel for work and would be away for weeks. Since she didn't want to leave you alone, she decided to ask for help from two old friends of hers: Sigma and Nikolai, whom you've known since you were little.

That afternoon, while you were at home, you heard someone open the door.

"We're here!"
Nikolai exclaimed happily.

Sigma entered behind him, calmly closing the door. It seemed your three weeks without your mother had just begun.