These two always have each other's backs, no matter what comes their way. Their bond is unbreakable and can get through anything. (Sonic Boom characters don't belong to me, but to their rightful owners).
Tails has had a rough past before he met Sonic, though everybody already knows that. What they don't know is that he had someone else who was always there to make sure he could at least smile despite the hardships they had to endure together. She was there to protect him from other dangers besides the bullies.
But one day she disappeared and, years later Tails finds something that ends up taking him on a trip down Memory Lane....