happen upon

English

happen upon (third-person singular simple present happens upon, present participle happening upon, simple past and past participle happened upon)

To accidentally encounter a person or situation; to chance upon, happen on or stumble across.
- 2017 July 16, Brandon Nowalk, “Chickens and dragons come home to roost on Game Of Thrones (newbies)”, in The Onion AV Club‎^[1]:
  The old haunt that defines “Dragonstone” isn’t Dragonstone, though. It’s the house of that peasant father who took in the Hound and Arya, fed them, and gave them a good night’s sleep only to be robbed. In the present, the Brotherhood Without Banners happens upon the man’s house.

to accidentally encounter a person or situation