Issabelle Barret is trying her best to run away from a terrible orphanage that she has been placed in after the death of her father, Harold. As a policeman captures her and takes her to the carriage she complains about the way the officer has a black horse tied up in back. Upon arrival to the orphanage Bella unties the horse and has him run away. Later she again runs away and finds her way to a ship where she stows away. The ship runs into a reef and breaks up. Bella is washed ashore and rescued by a Black Horse. She's found by Connie and Ted. Dr. Austin is rushed to ...

Isabella Barrett finds herself being cared for at Dr. Austin's farm, but has no memory of who she is or where she comes from. All she knows is that Black Beauty is hers.

Ted practices for the local Gymkhana competition.

Bella and Beauty have run away but Bella soon realizes she's lost. With a storm approaching, they must search for shelter.

Bella convinces Dr. Austin to let her sit for the Willstown Grammar School entrance tests along Ted. Meanwhile, Weeks has come up with a new ploy.

Dr. Austin reads Bella the letter that demands she return to the orphanage as soon as possible.

Everyone is excited by the discovery of the barrel lid: it not only proves that the Astoria was wrecked somewhere nearby, but gives Bella's story some validity. Bella asks Frank not to print the story in the Bugle, as she has already caused so much trouble.

The newly-minted detectives arrange their first meeting - but Frank has gone missing.

Bella has remembered that Mr. Cigar was on the Astoria. Frank realizes that the first thing they must do is to investigate the cargo list from the Astoria, in order to narrow down that was on the boat that Mr. Cigar may have wanted. Although Frank is supposed to be looking after the store, he and Bella take off for Willstown.

Bella accompanies Mrs. Mac in order to take care of an ailing Mrs. Crutchfield for the night. Her custody case is the next day, however, and she may not be at her best.

Despite being under strict instructions to behave herself, Bella allows herself to be goaded.

Frank inadvertently causes a gold rush in Yarrandilly.

Bella is confused about the decision she has to make about going to England with her Aunt Caroline. Caroline tells Bella that they may live in London and Paris, and Bella is horrified to learn that Beauty would not be able to go with her.

Ted has narrowed down the location of the gold, but the gang need a seaworthy boat. Fortunately, Ted knows where they can find one.

Although Frank as written an article in the Bugle saying that nothing was found in the Astoria shipwreck, Potch and Weeks ransack the Austin Farm stables in the hopes of finding the gold. Fortunately, the tin boat has been hidden underneath Caroline's car. Bella, Frank, Ted and Connie have a meeting to discuss their next move.

Walter and Bella try once more to open the tin box but realize that it will have to be cut open when Walter has more time. While this is happening in the stables, Connie tries to distract the doctor by telling him about a new puppy that the Jenkins are trying to find a home for. Caroline decides that she would like to go horseriding with Bella so they go to the Jenkins' farm.

Everyone is furious with the children for taking the law into their own hands. Frank tells an imprisoned Potch that his partner in crime is dead. Potch inadvertently tells Frank that his partner's name is Weeks. Back at the farmhouse Bella, Ted and Connie are given a huge lecture by the doctor, and their punishments are handed out for the upcoming month.

Bella and Caroline return from holiday in preparation for the wedding. However, Bella's friends treat her differently. Meanwhile, Frank issues the last edition of the Bugle.