Answer:
You heard a rumor from somebody.
Step-by-step explanation:
The grapevine in reference to when something is heard means that what was heard is a rumor (an unconfirmed truth) from somebody.
What is heard from the grapevine may be termed as an unverified truth.
It has nothing to do with what is heard outdoors, or what was missed or reference to what was heard from a person called grapevine.