Sophia Litrenta is planning to open a lemonade stand Tuesday.

The 9-year-old is still working out the details but she thinks she'll charge 50 cents a cup. She wants to raise $200, an ambitious goal that means selling 400 cups in the two hours her stand in Lutherville will be open.

None of this is exactly exceptional except that Sophia plans to donate her earnings to the Baltimore Police Department Mounted Unit, which had its funding cut and is now seeking the public's help raising $200,000 to keep officers on horseback for at least another year.

Donations to the nonprofit Police Foundation have been trickling in -- about $1,000 so far -- and police say they are negotiating for more substantial contributions. Meanwhile, it's adults and children, like Sophia, who are stepping up with little bits of cash.

In a shrewd marketing move, the Calvert School third-grader sent a letter promoting her affair to The Baltimore Sun. It was handwritten, in cursive, perfectly spelled and succinct. Its real hook came when Sophia noted that there will be "homemade cookies and brownies, too."

She listed only the family name on the return address, but it was enough to find her grandmother, who mentioned that Sophia wants a horse of her own. Did this little girl, who has never seen a Baltimore police horse, decide to save the police horses as part of a grander scheme to get a horse of her own? Does everybody have an angle?

Sophia's mother, Dawn, shot that theory down, sort of. "I don't think so," she said, noting that Sophia's step-grandfather is a retired New York City police officer. Dawn, who works for Long & Foster (the girl's father, Steven, is one of the owners of Looney's Pub) did say their neighbors have horses and that last summer Sophia volunteered to wash horses at a farm so that special needs children could ride them.

The cynical reporter felt good about proceeding.

Turns out Sophia loves animals, tells everyone she wants to be a vet and even spent an entire day at a veterinary clinic helping and watching sick pets get better. "My favorite animal is a hamster," Sophia said. And she has one she named Delano, after Franklin Delano Roosevelt.

Sophia and her nanny, Mindy Gottsagen, had planned the lemonade stand before settling on a cause. It was Sophia's tutor who spotted a news story on the police horses needing help.

She wrote the letter on her own; Mindy helped with an e-mail invitation to the neighbors and friends.

The lemonade stand will be open 2 p.m. to 4 p.m. Tuesday. Her mother gave permission for the home address to be published: 8609 Countrybrooke Way in Lutherville.

Police spokesman Anthony Guglielmi said cops are appreciative. "The Police Department is overwhelmed by the amount of public support we have received," he said.