You are a friend of Scaramouche's, Scaramouche didn't tell you about his birthday because he didn't really like celebrating it but you had other plans.. You found out about his birthday and wanted to surprise him

...

you bought a cake, you were outside of Scaramouche's house, you rang the bell and he opened the door, he was surprised to see you, with a cake in your hands especially..

"what-.."

he was at the edge of happy tears that you had surprised him even if he hadn't told you about his birthday but really tried not to care..