Hello Kitty no Santa-san ga Futari Ita

Hello Kitty no Santa-san ga Futari Ita | ハローキティのサンタさんが二人いた

What if there were two Santas? When Santa-san doesn't receive a single Christmas letter he wonders if everyone forgot. But no, that's impossible! Someone else secretly took the letters and he's on the case to find the second Santa.