Watson Doyle thought about his mom as he walked across the empty lot to the library. Sometimes she seemed to have superpowers.

    Once, she had known he'd bought a candy bar with his allowance instead of putting it into his Yoda piggy bank. Another time she seemed to be in two places at once. Stuff like that happened often.

    When Watson asked her to explain how she did these things she always said something like, "It's a mom talent. Someday I'll tell you how I do it."

    A mom that special needed a special Mother's Day gift. He could buy something, but he didn't have a lot of money. He could make her something, but at the moment he was a little short of really good ideas. He didn't want to make her just one more construction paper heart.

    At the library Watson checked out "The Wonderful Flight to the Mushroom Planet" and then went home, still wondering what to do about Mother's Day.

    He entered the house through the kitchen door and found his mother feeding Buster, their big old black-and-white cat. Buster seemed really interested until Mom put the full bowl on the floor. Buster took a couple of bites of his food, made a complaining meow, and trotted away. Watson knew he'd be back later.

    Mrs. Doyle glanced in Watson's direction as she rinsed the catfood spoon. "Been to the Twain branch of the library?" she asked.

    Superpowers, Watson thought. "How did you know that?" he asked out loud.

    Mrs. Doyle smiled. "Do you think you're old enough to be let in on Mom secrets?" she asked.

    "I'll be twelve soon," Watson reminded her.

    "All right, then," his mom said. "It's elementary, really. How many books did you have with you when you left for school this morning?"

    Watson thought back. "Two," he said. "My arithmetic book and my spelling book."

    "Right," Mrs. Doyle said. "And you had three when you came home: your arithmetic book, your spelling book, and a book with a library binding."

    "But that's easy," Watson exclaimed.

    "Sure it is. Once you know the trick."

    "But how did you know I got the book from the Twain Branch? I could have gone to the Steinbeck branch."

    "Look at your shoes," his mom suggested.

    Watson looked, but he didn't see anything unusual.

    "They show fresh scuff marks," Mrs. Doyle explained. "And bits of grit are caught in front. It's not hard to guess that you probably got the scuff marks and the grit crossing the big empty lot next to the Twain branch."

    "Cool," Watson said. If he could learn how to do his mother's trick he could amaze his friends.

    "Thanks," Mrs. Doyle said. "Want to see what I got my mother for Mother's Day?"

    "Sure."

    Watson and his mom went upstairs to the family room. Lying on the floor in front of the couch was a flat white box. It was empty.

    "Goodness!" Mrs. Doyle cried. "Somebody stole the cashmere sweater I got     for your grandmother!"

    "You mean there's a bad guy in the house?" Watson asked.

    "I don't know," his mother admitted. But she looked worried. "One thing is certain. The cashmere sweater is missing. Without it I don't have a Mother's Day gift for your grandmother."

    "How will we find it?" Watson asked.

    "You know my methods, Watson," Mrs. Doyle said. "Apply them."

    "You mean the Mom Trick?"

    Mrs. Doyle nodded.

    "Wait right here," Watson said. He ran to his room where he got a small spiral bound notebook and a pencil. He ran back to the family room and poised the pencil over the notebook. "I'm ready to find clues," he said.

    "I studied the crime scene while you were gone," Mrs. Doyle said. "There don't seem to be many clues."

    "Hmm," Watson said. "Let me see." His mom hadn't moved the white box. It was still empty and still on the floor.

    "You didn't leave the sweater on the floor, did you?" Watson asked.

    "No. The crook must have knocked the box there."

    "Sloppy," Watson said while he wrote the fact down in his notebook.

    Lying on one of the couch cushions was a ten-dollar bill. "How did that get there?" Watson asked as he pointed to the money.

    "It's mine," Mrs. Doyle said. "I was going to walk down to the grocery store with it and buy a few things."

    "What kind of crook would take a sweater but leave money behind?" Watson asked.

    Mrs. Doyle frowned while Watson made a note.

    Watson studied the room carefully, trying to see everything: the carpeting, the furniture, the pictures on the walls. What had been moved? What hadn't been there the last time he'd been up here? What had been there and was now missing?

    He got down on his hands and knees and studied the couch minutely. "Cat hair everywhere," he remarked and made a note.

    "How can that be a clue?" Mrs. Doyle asked. "Buster has the run of the house."

    "You're probably right," Watson agreed sadly as he stood up. Everything except the white box was exactly where it was supposed to be. Then Watson saw something that he was sure was another clue. "What's that?" he asked.

    Mrs. Doyle went to pick up something lying in the doorway. "It's white tissue paper," she said.

    "The same kind the sweater was wrapped in?" Watson suggested as he wrote in his notebook.

    "Absolutely," his mother replied. "Look: it has the name of the store on it."

    "Our crook must have left the room through that doorway," Watson said. He frowned. "That doorway leads to the upstairs hall." Watson was suddenly afraid.

    "What's wrong?" his mother asked.

    "There's no way out in that direction," Watson continued. "Unless the crook left by a second-story window he or she is still in the house!"

    "What should we do?" Mrs. Doyle asked.

    "I think we'll have to investigate," Watson said as he carefully peered around the doorway into the hall.

    Despite the big window at the end of it, the hallway was dim. Anything might be hiding in the shadows. "I'll have to get a flashlight," Watson said as he looked along the hallway's length.

    While his mom waited in the family room Watson ran down to the kitchen and rummaged through the tool drawer until he found a flashlight. A moment later he was back upstairs, aiming the flashlight beam into the darkness.

    Watson tiptoed into the hallway.

    "Be careful," Mrs. Doyle said.

    Watson crept along, listening hard, watching every detail, trying not to miss anything. He heard a noise and froze.

    "What is it?" his mom whispered from the end of the hallway.

    "Creaking floor board," Watson said. He stepped forward again, sweeping the flashlight beam before him.

    He aimed the light at a heat register. During the winter heat came up through the grid from the furnace in the basement. "What's that?" he asked.

    "Looks like something caught on one of the screws holding the grid in place," Mrs. Doyle said. She walked into the hallway, passed Watson and knelt at the register. From a screw head she unwound something that looked like cotton fluff.

    Watson knelt beside her, using the flashlight to illuminate the tiny fiber cloud. "What is it?" he asked again.

    "Cashmere," his mom told him. "Why would anybody steal a sweater and then drag it along the floor?"

    "I know," Watson said. "And I know where the sweater is, too."

    No longer afraid, Watson confidently walked along the hallway to his room, where he stood before the closet. The door was open just a little, which was exactly what he'd expected.

    When his mom entered and stood next to him, Watson opened the closet door. There was Buster, sleeping on the closet floor, curled up on the sweater. He yawned up at them.

    "This explains everything," Watson said. "Buster had no interest in money, which is why the crook left the ten-dollar bill. The cashmere on the heat register cinched my theory. Only Buster would have dragged the sweater along the floor."

    "Once you knew who took the sweater, finding it was easy."

    "Elementary," Watson said. "Buster's been sleeping in my closet for weeks."

    Gently, Watson lifted Buster, and Mrs. Doyle rescued the sweater. "It doesn't look too bad," Mrs. Doyle said as she inspected it. "Beside, my mother likes Buster. I think she'll be kind of charmed by what happened." Buster was already asleep again.

    Watson and his mom went back to the family room where she rewrapped the sweater in the tissue paper. While she did it, Watson had a wonderful idea for a Mother's Day present -- something really unusual.

    He signed the notebook page where he'd jotted down all the clues and handed the notebook to his mother.

    "What's this?" Mrs. Doyle asked.

    "My Mother's Day present to you. To remind you of our super adventure together."

    Mrs. Doyle grinned and then kissed Watson on the forehead. "You're pretty super, yourself," she said.

Mel Gilden is the author of the Fifth Grade Monsters series of mysteries. He used to write his mother a poem every year for Mother's Day.