School boy detective, Fletcher "Half" Moon, is keen to crack his first case, and an unlikely new detective duo is born. Newly qualified from Bob Bernstein's online school of detecting, "Half" Moon is eager for his first case. When the winner of the art club competition has one of his paintings stolen, it transpires that this is not the only recent theft at the St Jerome's school and the new headmistress, Principal Quinn is already on the case. According to school reporter, Mia, the prime suspect is Red Sharkey, whose family members are no strangers to being top of a suspect list. But when Moon realises that he is following the wrong trail, an unlikely alliance is forged and a new detective duo is born.

Hungry for their first proper detecting case, Fletcher Moon and Red are on the trail of a mobile phone thief at St Jerome's who is bullying other children at school by text. Mobile phones are going missing at St Jerome's. Hungry for their first proper case, Moon and Red are on to it. They soon realise that their thief is also sending abusive texts, but not before friends fall out and alliances are destroyed by the text bully. But will Moon and Red be able to find the thief's identity before complete anarchy sets in? Meanwhile Moon's sister Hazel longs for Goth Dogboy to notice her – but he only has eyes for Red's sister Genie. When he offers the perennially skint Genie a ticket for a gig, she vows to somehow get the money – Hazel is on her tail. But will Hazel's quest to attract Dogboy's attention be a lost cause?

A swimming trial is sabotaged, a betting ring busted, and pint-sized private eye, Fletcher Moon is forced to conquer his fear of water. When someone tries to sabotage training for St Jerome's star swimmer, Harriet "The Fish" Thompson, by putting purple die in the swimming pool, fully qualified young private detective Fletcher Moon is determined to find the culprit. His profound fear of water, however, threatens to jeopardise this water-based investigation. Much to ace reporter Mia's amusement and Moon's embarrassment it looks like he may fail to conquer his fear. Meanwhile headmistress Quinn apprehends Harriet's fellow swimmer Shell and Moon's crime busting partner Red, ignoring the protests of innocence. But why are The Pinks so keen that the swimming trial be cancelled?

A smudge on a prefect badge leads Moon and his detecting sidekick to discover criminal activity in an unlikely quarter. It's a proud day for Moon's sister Hazel as she is sworn in as a junior prefect, but more importantly she is now able to make eyes at head boy – and school heart throb Nigel. For Moon a new investigation beckons as a mysterious note appears on his locker on which is written "stop them" with a prefect's badge pinned to it. Closer examination reveals clues which suggest some illicit activity linked to Pupil Enterprise Week – but what? Meanwhile Red's brother Herod is doing a surprising roaring trade on his cake stall, and the object of Hazel's affection, squeaky clean Nigel, has the finger of suspicion pointed at him over secrets from his past.

What appears to be the ghost of Mr Pickles is spotted in the disused science lab – but can Moon and Red solve this paranormal mystery? The reported sighting by a fellow pupil of a ghost in the disused science block, compels private detective Moon to try to become a temporary psychic investigator. April challenges Moon to prove that Devlin has made up the appearance of evil old Mr Pickles. Initially sceptical, Moon find his beliefs challenged when "evidence" of the supernatural seems to present itself. It's time for Moon and Red to set up a stakeout in the old lab. Armed with various gizmos designed to record evidence of paranormal activity, they wait. But things are not quite what they seem. Green smoke, mysterious banging and a gruesome monster – will the boys solve the mystery?

The disappearance of a valuable artefact, and an unexpected appearance by "Half" Moon in the school play – just another ordinary day in the life of the schoolboy private investigator. The disappearance of a valuable artefact during a performance of the St Jerome school play causes panic among the actors – it belongs to headmistress Quinn. Moon's sister Hazel meanwhile is worried for a different reason – she thinks her chances of kissing the leading man in the final scene could be scuppered if this crucial prop is not found. There is no time to lose. Moon, Red and Mia go backstage to begin their investigations and on discovering that an Inspector Moon has been written into one of the play's scenes, Moon decides to take up the gauntlet making an impromptu appearance on stage. But who did steal the phoenix, and can Moon recover it before it's too late?

Red's brother Herod is in trouble again. Another tricky investigation for "Half" Moon as the school's zero tolerance on misbehaviour starts to bite. A zero tolerance on misbehaviour at St Jerome's School has taken a sinister new turn for the pupils as headmistress Quinn sets up Pupil Reform Initiative for the Socially Offensive Non-Compliant (PRISON). And Quinn has Red's brother Herod in her sights. Meanwhile Moon notices that Quinn only appears to be sending the boys in Moon's year to Prison, after they have been accused of all manner of "crimes" by April and The Pinks. Something is clearly afoot and Moon, reunited with Red, decides to dig for more evidence. A stakeout of April's house by the detecting duo reveals a gruesome truth.

Red has to work alone on the latest Moon investigation and ace reporter Mia is temporarily recruited into The Pinks. Mia discovers that being in the gang isn't as appealing as she had thought. Red is left to solve the latest "crime" at St Jerome's School when private investigator Fletcher "Half" Moon is confined to bed after injuring his ankle during a case. It is the eve of auditions for the prestigious Riverhall Music School. Mercedes, one of The Pinks, and a budding pianist, is distraught to discover that her lucky charm – Apollo the unicorn – has been stolen. Foul play by one of her fellow candidates Fran or Billy is suspected. Mia attempts to build Mercedes' confidence, but the arrival of a ransom note knocks Mercedes for six. Moon, meanwhile, is keen that she doesn't give in to the hostage taker's demands. But will Moon be able to identify them before time runs out?

Half Moon and his investigating partner, former bad boy, Red Sharkey try to discover who is behind a nasty smear campaign. Red's brother Herod is elected as Year Rep and this class clown's popularity soars as he decides to implement some rather outlandish plans. When pictures of Herod smashing the headlights of Headmistress Quinn's car appear all over the school, it looks like a smear campaign has been launched by a mysterious foe. But clearing Herod's name could be a difficult job for private investigator Moon and his partner Red as they set out to restore his reputation. The main suspects are Herod's rival in the presidential race, but could the true culprit be much closer to home?

Half Moon and Red are determined to get to the bottom of the mystery of a missing exclusive interview tape. Ace school reporter Mia proves her journalistic credentials by scooping a much sought after interview with "it" girl and chart-topping star Shona Beiderbeck. And if that isn't enough good news, Ben, an exchange week pupil placed in her care, puts a spring in her step – could Mia be in love? When the much anticipated interview is stolen, Mia is reluctant to let Moon and Red investigate the case and tells them just to forget it. But could the object of her affections have his own reason for also hoping Moon and Red drop the case? Meanwhile Papa Sharkey is investigating a mystery of his own. Two of his kids have come home with black eyes and he's determined to get to the bottom of it before the Sharkey name is dragged through the mud once again.

Moon's judgement on his latest case is clouded as he goes "ga ga" over a girl. When a netball trophy is stolen at Half Moon's school the finger of suspicion points at the kids in the metal work club and a race against time to uncover clues begins Meanwhile Moon's sister Hazel is in charge of sponsorship money for the fun run – and she has the key to the school safe to prove it. Moon is allowing his crush on a girl at school to cloud his judgement on the suspects in the case, but has "faultless" Chelsea actually been framed by April, and is there no end to the leader of the Pinks' deviousness.

School talent contest hopeful, hypnotist Ruby, casts a spell over her school colleagues in Half Moon Investigations. Unpopular hypnotist Ruby is convinced that she will win the school talent contest while her fellow contender Nikky has to pull out when her costume is sabotaged. Could there be a connection? Moon, however, has more important things to worry about – his private investigator's badge has gone missing. But how much will this very personal loss cloud his professional judgement?

April launches her most dastardly plan yet but will she really try to sabotage the school dance without the support of the Pinks? Half Moon and his partner Red think April is behaving suspiciously – and they are proved right when they discover she plans to sabotage the school dance. But what evil lengths will she go to when her Pink posse start questioning her judgement? Moon's sister Hazel is upset that her boyfriend Stevie is spending the summer in Ibiza as a DJ. Confusion reigns, though, when the school decks disappear and foul play is suspected. Can there be an end to the battle of wills between Moon and April in this final episode of the current series of Half Moon Investigations?