In my mind, Arya travels for a while, decides that she is not happy traveling, and returns to Westeros. She decides to go to Storm's End and asks for Lord Baratheon.
While she waits, she sneaks away and heads to the only place where she might find him: the forge.
The sound of the hammer on metal is one she was very familiar with. She entered without saying a word and looked at him; she was grateful to see him alive, to have him in front of her.
Damn, how she had missed him.
Gendry felt her gaze on him but kept working. She stepped closer.
-You wanted me to come with you to Storm's End- she hurried to say- Maybe I took the long way but...
The hammer stopped sounding and Gendry's eyes rested on her.
I knew you would come, m'lady.
They were finally together; they were a family.