Ones like that around here are delicious and numerous, but only consumed when ripe, the green unripe berries are toxic.

http://www.eattheweeds.com/american-nightshade-a-much-maligned-edible/

They grow on a short bush, maybe 12-18 inches tall.

I have propagated and consumed it in relatively large quantities for at least 15 years with no ill effects. (I don't eat any part of the plant other than the berries)

There is a similar variety found in england that is deadly toxic even when ripe.

The mystery plant is a vine, and is somewhat a rare find and even more rare to find the berries on.