Query Letter Question

(Wow, I haven't posted for a while. How did that happen? Anyway.)

Hello, again! I'm back, at least for a little while. I'm going to be pretty busy this next week with packing so our family can get ready to move into our new house next week (!!!). I feel like we're getting ready for this fantastic journey, when in reality we're moving two minutes down the road. But hey, a new house, however far away it is, is still an adventure! (I think my brother is most excited about the intercom system.)

But I'm getting distracted. I have a question for anybody out there that has advice for me. It's about query letters. When writing a query letter for a picture book, should you tell the agent everything that happens in the book, ending and all, or not? For example, should I write:

Casper is a ghost. He’s also hungry. He wants a peanut butter and jelly sandwich, but there’s a slight problem. He’s out of peanut butter.

Or:

Casper is a ghost. He’s also hungry. He wants a peanut butter and jelly sandwich, but there’s a slight problem. He’s out of peanut butter. Casper is willing to try anything he can think of to fix this, and he does. Once he’s able to get his hands on some peanut butter, though, he discovers a new problem. He used up all the jelly.

I've never queried a picture book before, so I'm not sure what to do. I'm open to suggestions, so please comment away!

A Lengthened Version of the Story In My Post Called "Short Story"

I'm going to try to put this story in a magazine. Please give me suggestions and comments. Thanks!

The ghost was eating a peanut butter and jelly sandwich. Well, it was just a jelly sandwich. The ghost, named Casper, had forgotten the peanut butter.
“Oh no!” Casper exclaimed. “I forgot something!”
“What did you forget, honey?” Casper’s mom, Catherine, floated in worriedly. She was in the middle of getting her makeup on. Only her top lip had red lipstick.
Casper frowned.
“I forgot the peanut butter on my sandwich. Do we have any left?”
Catherine shook her head.
“Sorry, sweetie. I used up all the peanut butter on the peanut butter cookies.”
Casper scowled at the cookies on the counter for ruining his sandwich.
Casper sighed as his mother floated back towards her bedroom. What was he going to do? He was very hungry, but all he wanted was a good old PB&J sandwich.
Casper suddenly had an idea. He grabbed one of his mother’s peanut butter cookies and spread the grape jelly on top of it. Then he put the cookie in between two slices of bread. But as soon as Casper tasted it, he spit it out into the sink.
“Bleck!” he sputtered. “Peanut butter cookies and grape jelly do not go well together!” Casper threw out the sandwich.
“What was that?” Catherine called from her bedroom. “Did you call me?”
“No, mom! I’m just trying to make my sandwich without using peanut butter!”
“Good luck with that.”
Casper tried again to make his sandwich.
Casper scooped up a handful of peanuts and dumped them into a bowl. He mashed them with a potato masher.
The peanuts had only mashed half way, but they would not mash any more. Casper put the partially mashed peanuts in between another two slices of bread spread with grape jelly. Casper tried the sandwich, but it just wasn’t the same as all the way mashed peanuts. So he threw out that sandwich, too.
Casper decided to try one last time to make his sandwich without peanut butter.
Casper took out his mother’s favorite kind of butter. Apple butter. He spread the apple butter and the grape jelly on another two slices of bread. He put the apple butter away and tried the sandwich.
“It’s just not the same,” Casper sighed. He threw out his sandwich.
“Casper!” Casper’s mom came floating down the stairs. “We’re going to the Ghostery Store.”
“Ok, mom.”
Casper went outside and got into the car. Not long after that, he and Catherine drove off.
Casper unbuckled his seat belt as Catherine parked the car in the parking lot. They floated inside.
“What’s on the Ghostery list?” Casper asked. He loved to help out with the shopping.
“We need apples, noodles, green beans, potatoes, and celery.”
“We also need peanut butter,” Casper reminded his mom.
“Right. Peanut butter.” She took a pen out of her purse and wrote it down on the list.
“How about I give you half the list and I take the other half. Ok?”
“Ok.”
Catherine tore the list in half and gave one half to Casper.
“I’ll meet you at the self-checkout counter.”
“Ok. Bye!”
So Casper went off to find the potatoes, celery, and peanut butter. The potatoes and celery were easy. There’s only one kind of those. But the peanut butter was harder. Should he go chunky or smooth? Skippy or Jif? Small jar or large jar?
Finally he decided to go with a large jar of smooth Skippy peanut butter. Casper floated off to the self-checkout counter where his mom was waiting.
Catherine took the food, scanned them, paid for them, and took the receipt.
“Let’s go home, now. It’s almost dinner time.”
“Yes! And now I can make my peanut butter and jelly sandwich!” Casper was excited.
Casper and Catherine drove to their house. Casper leaped out of the car and floated inside very fast.
“Uh-oh,” Casper said as he got out the peanut butter and the bread. “I’ve got a problem.”
“What’s the matter?” Catherine asked.
“I used up all the jelly.”