As Nate the Great sets to work on his first international case, he searches for a lost "something" and saves the King of Sweden from a troublesome traveler.

When a baseball game is stopped because of a lost ball, Cam uses her photographic memory to find the ball.

When Max's dog Puppy gets lost, it is not until both Max and Puppy have the same idea that they finally find one another.

Molly's parents try various methods to help her remember her mittens but nothing seems to work.

Disappointed that her monster costume does not frighten anyone, Katie Woo still finds a way to have a happy Halloween.

When a cow loses her moo, she searches to see if another animal in the barn has it.

When Adele walks her little brother Simon home from school he loses one more thing at every stop: his drawing of a cat at the grocer's shop, his books at the park, his crayons at the art museum, and more. When Simon's older sister, Adele, picks him up from school, he has his hat and gloves and scarf and sweater, his coat and knapsack and books and crayons, and a drawing of a cat he made that morning. Adele makes Simon promise to try not to lose anything....

Mini finds a dog in the park wearing shoes but no collar and begs to keep him, but soon she realizes that whoever put the shoes on him loves the dog, as well.

Emmett loves his bright blue cape, and wears it everywhere to be Super Emmett. One day, his mom says its time to wash it, and hangs it outside to dry. When Emmett goes to look for it he finds a bird has taken it and made a nest out of it. His mother has a good idea to help him be Super Emmett again.

Unless Annie's house key can be found, Annie will have to cancel a birthday party for her dog, Fang, and master sleuth Nate is determined to solve the perplexing mystery.