The story is about a boy named Kalle Blomkvist who with his friends solves crimes. But also play the battle between the red rose and the white rose with his rival friends. But everything changes when Kalle Blomkvists friend finds a dead man in a cabin and then must his friends and he find the murdurer.

Max can hardly believe his luck: In a retirement home, he has finally found a gang that will let him join! Admittedly, it's the oldest and most wrinkly gang in the world - but that doesn't matter. He's found the best friends a 10-year-old could wish for in the elderly Vera, Horst and Kilian. Especially when, like Max, you're bullied in your new class and need help. But the gang's attempt to improve his school situation backfires. Horst, a former Bundesliga soccer coach, challenges Max's over-ambitious gym teacher Stöhle to a soccer duel: the school team including Laura and Ole against a selection of old geezers plus Max! And then the castle is haunted and a new case begins...

The name Michael O'Hara has become synonymous with law enforcement. There have been three generations of Michael O'Haras and all have been exemplary policemen. When Michael O'Hara III's child was born he was told that they would not be able to have any more children, and there has always been a Michael O'Hara, so he named his child Michael O'Hara IV despite the fact that she is a girl. Now Mike has a tendency to get involved with police matters and not always with good results, which annoys her father. And despite being told repeatedly to stay out of it, she continues her amateurish detective activities.

When her best friend's father is falsely accused of stealing the town's prized jingle bells, a young amateur sleuth and her friends must find the real thief before Christmas.

Henkka Virtanen finds evidence of a possible crime on his way to school. With his friend J.K. Kivimutka, the boys decide to investigate what has happened, because these criminal cases are the responsibility of the detective agency they have set up. When it turns out that mailboxes in the area have disappeared during the night, the detective bureau has already two crimes to solve. A fun and exciting adventure begins, in which the boys also have to face their own fears.

The Viennese detective children Biggi, Patrick and Luke find a key in dragon form, and their curiosity is aroused. They realize that the sinister Lady Q is interested in opening the legendary moon palace and find the elixir which is believed that promises eternal youth. The Tigers must prevent that Lady Q enters into possession of the priceless liquid.

Valo, who recently moved to Raahe, gets bullied. After rescuing an abandoned dog, Valo finds a friend in it, whom she names Roi. Together, the friends end up investigating the mysterious disappearance of a neighbor boy.

Late one night, Billy and Kade Ruckman see their neighbor, Michael Chambers, murder a woman, but Chambers has a story all set to convince their mother Vicky, that it was just a rehearsal scene from an opera. The only ones who can help them find the body in Chambers' house before he moves and gets rid of all evidence, are their friends, Jimmy, Eddie, and J.J., who are determined to find the body before Chambers finds them.

A call for help from gallery owner Mr. Prentice leads the three detectives into a new adventure: his apartment is said to be haunted. When the Carpathian dog, a valuable work of art, is also stolen, events spiral out of control because all the residents have a motive. As the suspects are eliminated one by one, the three detectives find themselves in the middle of their most exciting case yet.

The three investigators want to go on a road trip during their vacation, but just as they are about to set off, the phone rings and an unknown caller hands the trio of detectives their latest case: the archaeologists belonging to the secret society Sphinx are carrying out illegal excavations and selling the stolen art treasures. Their next target is the supposedly cursed island of Makatao.

A wealthy student with too much fashion sense, her equally rich friends, and her rival/superior from the school paper work together to solve the case when their teacher goes missing.

Three friends find a secret tunnel under the ruins of a church that leads them to the basement of a dilapidated house and, incidentally, a group of counterfeiters.