Question

Is a plot the same thing as a summary of the story? If not, what's the difference?

Answer 1

No.

Explanation:

Here is a plot diagram

Plot is the five main components of a story, shown in the diagram above.
Exposition- beginning
Rising Action- events leading up to the climax of the story
Climax- the most intense point in the story, usually where the conflict is resolved
Falling Action- things that happen after the climax
Resolution- the end

A summary, is a describing the main points in the story in a couple of sentences. Here is an example of a summary of The Three Little Pigs.

The Three Little Pigs is a fable about three pigs who build three houses of different materials. A big bad wolf blows down the first two pigs' houses, made of straw and sticks respectively, but is unable to destroy the third pig's house, made of bricks. (https://en.wikipedia.org/wiki/The_Three_Little_Pigs)

So no, a summary isn't the same thing as plot.