The story is set in London and follows Katrielle as she solves mysteries with her talking dog Sherl.
Episode 1
Katrielle Layton, an intrepid investigator who heads up the three strong team at the Layton Detective Agency alongside her assistants Ernest and Sherl, takes on a case involving a mysterious house in which a new tenant's family suddenly and inexplicably disappeared.
Episode 2
Katrielle is approached by Pastel, a struggling musician, who claims that a strange dress he bought for his wife Olivia is causing her to become possessed.
Episode 3
A young woman named Liv seeks Katrielle's help after she is visited by her late husband, Andy, apparently returned to life as a zombie.
Episode 4
Inspector Hastings enlists the Agency's assistance in tracking down a serial jewel thief before the criminal can enact their most daring heist yet.
Episode 5
The team becomes involved in a new case when a young man approaches the Agency in the hope of discovering a way to resume an implausible lucky streak.
Episode 6
Katrielle stumbles upon a fresh mystery when a classmate of Ernest relates the story of a mysterious bus journey that seemingly transported them back to the time of their childhood.
Episode 7
The Agency is visited by a young boy named Leo who fears that the mysterious hero of London's streets, Ratman, has been kidnapped.
Episode 8
The team are summoned by Inspector Hastings to the site of a seemingly impossible burglary: one hundred million pounds have vanished from a high-tech bank vault.
Episode 9
Katrielle is called to the estate of a millionaire gourmet with an unusual request: her pet has gone missing, and she wants it found before her dinner party commences.
Episode 10
Rosa, an old acquaintance of Katrielle's father, visits the Agency with information relating to the Professor's disappearance eleven years ago.
Episode 11
The Agency attend the premier of a much-anticipated film, only to discover mid-scene that the moment of the climactic kiss has disappeared from the reel.
Episode 12
Relaxing on a public holiday, the Agency team become embroiled in a highly unusual case when a desperate Inspector Hastings pleads their aid in finding a last-minute gift for his wife's birthday.
Episode 13
Katrielle takes on a new case involving a young pianist who is being plagued by appearances of a doppelgänger.
Episode 14
Katrielle and the team are left puzzled when Hastings requests their help on a case where the culprit has already been uncovered.
Episode 15
The Agency receives a new mystery to solve when a young farmer details the unexplained appearance of strange patterns in their wheat fields.
Episode 16
Katrielle investigates a young girl on behalf of her concerned mother, who believes her daughter is able to predict the future.
Episode 17
Hastings turns to the Agency trio when London is menaced by a mysterious growling giant lurking in the fog.
Episode 18
Travelling on board the Molentary Express for a special solar eclipse tour, the team find their attention divided when clients old and new describe a sequence of strange events.
Episode 19
The team are summoned by a young heiress whose estate is seemingly being haunted by a host of ethereal apparitions.
Episode 20
Rosa returns to continue her story, and reveals the link between Katrielle's origins and the Professor's disappearance.
Episode 21
In search of sweets of legendary reputation, Katrielle is hooked when she is told that she will have to prove her connoisseur qualifications by locating the nearby store herself.
Episode 22
Katrielle is invited to the unveiling of Agency acquaintance and child genius Bengary's latest invention: Sketman John, a robotic renaissance-manservant.
Episode 23
One of London's famous "seven millionaires" requests the team's investigative attentions after discovering a love letter written by his much-adored daughter, Allie.
Episode 24
Hastings employs the Agency's efforts in the search for a hand belonging to Big Ben, in the hope of recovering it before the arrival of a foreign ambassador.
Episode 25
Katrielle joins an investigation at London's Riverside Festival into a tragic incident that took place on the banks of the River Thames, mirroring a local legend.
Episode 26
Ernest recounts the time he was accused of stealing valuable research papers on his first day at Gressenheller University, and his resultant first encounter with Katrielle.
Episode 27
The Agency team are forced to go on the run from the law after Katrielle finds herself the prime suspect in a murder investigation.
Episode 28
Katrielle finds yet another mystery on her hands when a celebratory treasure hunt held on a luxury cruise ship's inaugural voyage goes awry.
Episode 29
The Agency trio travel to the Scottish Highlands after receiving a request to investigate recent sightings of the famous "Nessie" creature on the waters of Loch Nem.
Episode 30
Strange goings-on in a suburban domicile lead the Agency's latest client to seek their advice as to whether or not his wife has become a witch.
Episode 31
Strange goings-on in a suburban domicile lead the Agency's latest client to seek their advice as to whether or not his wife has become a witch.
Episode 32
Katrielle takes on the task of reuniting a young woman with the object of her affections, a man who claimed to hail from another planet.
Episode 33
Bengary challenges the Agency team to solving their most ambitious case yet: a murder mystery from the realm of his own imagination.
Episode 34
On the tail of the fabled Relics, the Professor and Luke of eleven years prior close in on a shadowy figure, while Katrielle and co. trace their whereabouts in the present.
Episode 35
The paths of the parties past and present converge in Southampton, as the final hours before the duo's disappearance count down.
Episode 36
Angel Arrow CEO Bergman calls on the Agency after the label's four showcase dresses vanish two nights before the world's biggest fashion show.
Episode 37
The Agency is visited by Mintan's fellow farmworkers, seeking the team's help after a sudden personality change in their old friend transformed him from hard-working agronomist to obnoxious gambler sporting an improbable winning streak.
Episode 38
Katrielle joins a Scotland Yard blockade erected around a bridge due for demolition after Bengary's latest Sketman, Punch, takes up residence. With the giant robot incapable of vocal communication, Katrielle must figure out the reason behind its behavior to put an end to the standoff.
Episode 39
An Agencybound Katrielle receives a call from babysitter Kelly, whose concerns are centered around her latest assignation appearing to include an invisible infant.
Episode 40
Spurred by a horoscope warning that the only recourse to having "the worst day of the decade" might be to spend it with a friend, Katrielle decides to spend the day with Emiliana at a local café, unaware that the adroit analyst has her own plans. Emiliana challenges Katrielle to play at guessing the professions of their fellow customers, pitting the former's highly professional profiling skill squarely against the latter's esoteric and impulsive investigation methods.
Episode 41
In the wake of discovering a recurring phantom figure appearing in his images, London Times photographer Pete contacts the Agency, fearing that he has fallen victim to a curse.
Episode 42
Tired of being treated like the Agency dogsbody, Sherl jumps at the chance to conduct his own investigation into the reported death of a beloved member of the neighborhood pack.
Episode 43
The Agency trio are recruited by an old client with the goal of completing a challenging "virtual reality game".
Episode 44
After an incident involving a misunderstood "all-you-can-eat" restaurant opening and Katrielle's insatiable appetite, the eager investigator accepts the offer of a cook-off challenge to settle her debt.
Episode 45
Supernatural superfan Andrea, youngest of the seven millionaires, invites Katrielle and a selection of her acquaintances to compete in a game of "Ghost Escape".
Episode 46
The Agency trio's trip to the Marylebone Museum of Art to see the famous Mona Lisa takes a strange turn when Katrielle is informed that the museum's entire collection has been surreptitiously replaced with an array of Lisa-centric works.
Episode 47
Receiving an invitation addressed to her father requesting attendance of a puzzle-solving event hosted by the mysterious Ariadne, Katrielle and company find themselves reunited with all seven of the renowned London millionaires at the deserted mansion of a deceased magnate.
Episode 48
With the realisation that the Seven are hiding a secret, Katrielle's investigation takes an unexpected turn, and as she pieces together the mystery, the true identity of their host is revealed.
Episode 49
In the wake of having located Luke and the Professor, Katrielle's investigatory instincts refuse to let her rest, compelling the team to follow the trail of the mysterious "Aldebaran" to his palatial home in search of answers.
Episode 50
The two parties united at last, their long journey comes to a climactic conclusion in a fateful showdown at the Greenwich Observatory with the man behind the entire conspiracy.
