Maisy Watson is the youngest child and only daughter of John Watson. She is also a charge of Charlotte Holmes who babysits her.
Ryder Watson - is Maisy's older brother. The two always tease each other and despite the way they act towards each other they're very close.
Charlotte Holmes - Charlotte is Maisy's a babysitter who has been watching her since birth because if their families connections. The two are as close as sisters.