If you break a sentence up with an em-dash (which doesn’t belong in this example anyway), don’t capitalize the first word after it. (Also don’t be a smart-ass. Of course you’d capitalize the first word after an em-dash if it was a proper name.)
I replaced the em-dash with a semicolon because the two parts of the sentence seem too closely related to need to be split into separate sentences, but you could use a period instead of you just hate semicolons.
Who’s is a contraction of who is (or sometimes who has); it isn’t a possessive pronoun. To show possession, use whose.
There are also a couple of typos in the second line of the example, thrown in to see who’s paying attention. 🙂 Kudos to anyone who caught ’em.
Throwing a coin in a fountain and making a wish doesn’t grant the wish; taking the coin out of the fountain does. A homeless man fishes some coins out of a fountain. Tell the story of the people whose coins he took.