Although it’s not quite incorrect as it is, I recommend changing return home to find to return home and find, because of the slight difference in meaning. (You didn’t return home for the purpose of finding whatever it is; you returned home, and then you found something. This is about sequence, not cause and effect.)
Because it’s part of the proper name of this mythological artifact, you should capitalize Holy as well as Grail.
Fun fact: Although the past tense of read is read, the past tense of lead is… led. Don’t mix ’em up.
After getting a great deal on an antique drinking glass from the old man at the market, you return home and find a man in full plate armor in your front yard. He tells you his quest for the Holy Grail has led him to this place.
‘Nother fun fact: At the time when anyone would have been questing for the Holy Grail, full plate armor wasn’t yet a thing; that didn’t happen until the late Middle Ages. This guy ought to be in mail or maybe partial plate.
(Don’t you just hate it when you come home from a shopping trip and find some weirdo in your front yard…? 🙂 And yes, that is a veiled reference to backstory for a character or three — four, now — in my clone-sibling’s fiction. At least the POV character in the glitch example got a questing knight instead of a couple of people fleeing ‘inter-dimensional ninjas.’)
And I must tell you about this: WordPress’ brilliant (I say with much sarcasm) spelling/grammar checker insists that I actually mean questing night. *sigh* Yes, that makes soooooo much more sense.