Robin loves him before she understands him.

A few glasses of Firewhisky at Grimmauld Place get Sirius reminiscing about school days and in the process telling Tonks a little more about Remus. Marauder friendship and a healthy dash of R/T.

She had almost given up on hearing from him when he shows up at her door... HBP era, as Remus is forced to take refuge from his mission with the pack.

Filling in the rather significant gap in Lupin and Tonks' relationship between the infirmary and Dumbledore's funeral in HBP.