Returning home after five years away, Mary finds herself lost and disconnected from the people she once knew, until a visiting tourist shows her a side to the city and to herself she never knew.

"Returning home after five years away, Mary finds herself lost and disconnected from the people she once knew," - This is her internal journey but it's not very cinematically intriguing.

"...until a visiting tourist shows her a side to the city and to herself she never knew." - This feels more like the meat of your story. If you can flesh out what actually happens when these two meet and what happens afterward, you'll have a more enticing logline.

When you mention "the city", I assume you mean NYC? For some reason, your logline reminded me of Before Sunrise.

Protag = Mary; try to avoid proper names, instead describe what she is. ex. disaffected woman, or even better, disaffected [insert occupation]
Antag = ?
Goal = reconnect with her family and friends? herself?
Stakes = more disaffection?
Hook = ?

Best of luck!