PLUS ONE
Plus-one: a person's guest at a social function.
Plus: with the addition of; i.e. "two plus four is six"
:a mathematical operation of addition.
:an advantage: "knowing the language is a decided plus"
One: A number, usually accepted as the first!
Therefore:
One plus one equals three; eg: Mum plus Dad equals Baby
In sport when the two opposing teams have the same score you often hear:
One more each and they’ll be even
So it is with solving this cache puzzle
That’s enough clues
Enjoy the puzzle and the joy of the hunt
Cheers OldSaint