the difference between action and plot

Still struggling with the difference between action and plot. Okay, action is simple. Three kids go surfing. One gets hit on the head and the other two have to rescue him. Action. But, how does this fit with the plot. Maybe the plot of the story is that these three boys find a starving whale and have to figure out why. They discover someone's dumping chemicals into the bay, and have to stop them. Plot. But that plot needs some action. It takes place in a bay, so how did the boys find the whale? Maybe they were surfing. See what I'm getting at here? Sometimes action has to come in and back fill the plot. Fill it up. Make finding out stuff exciting. So even if the plot's not about something like finding dying whales, but more like discovering that someone you love is being hurt, something we might not see a lot of, because these things take place behind closed doors, there still has to be action to keep the story active and alive as we uncover the little clues that show us the plot. Am I making any sense here? Does this sound even remotely right? Or have I got it all wrong?

Here's another example. I'm working on a story in which a 12 year old girl learns about corruption. This is a story that could have many different plots. It's not an action story; it's more of a coming of age story. So how to build a plot full of action, so that it's not a boring snore while we learn what she learns? I've decided to set the story within two families, one of which is big and has a lot going on like weddings and birthdays. Lots of possibilities for action. But the plot takes place above all that. It slides into the action obliquely, letting hints fall here and there, until she pulls it all together and understands the big picture.

But then maybe I'm making things more difficult than they should be. Maybe plot and action are the same thing and I'm just making work for myself. Thoughts?