C20 How is that possible?

"Annika!".

Tallulah called in horror as Annika rolled down the long flight of stairs continuously.

"Nik!".

She heard Mateo call and run to Annika who had already fallen from the last step to the floor. Blood was oozing out from underneath her head.

Mateo held Annika's head and placed it on his thighs as he looked up the stairs at Tallulah furiously