August 1911. Emily Hardcastle and her inimitable lady’s maid Florence Armstrong are enjoying a fine summer until Harry, Lady H’s brother, turns up out of the blue with a mystery for them to solve. A routine parachute test at a local aeroplane factory has gone horribly wrong - with pilot Dickie Dupree plummeting to his death. Harry is certain there is more to this ‘tragic accident’ than meets the eye, having discovered that someone at the airfield is leaking top secret intelligence to foreign rivals.

When London’s finest jazz musicians, the Dizzy Heights, are booked to play the glitzy Midsummer Ball at a country house in Oxfordshire, they expect a weekend filled with flappers and toffs having a roaring good time. But the festivities at Bilverton House take a turn for the worse when the group are stranded by a summer storm. And when a member of the Bilverton family turns up dead in a locked room in an apparent suicide, Skins, Dunn and Ellie realize this is going to be a much tougher gig than they thought.

July 1910. Lady Hardcastle and her tireless sidekick Flo have finally embarked on a long-overdue seaside break. But just as they’re wavering between ice creams and donkey rides, their fellow guests start to go missing - and the duo find themselves with a hysterical hotel manager and a case to solve. The first to disappear is Dr Goddard, a scientist doing something terribly top-secret for the government. 

A scoundrel lies dying, and he makes his confession; his sins were despicable, and he wants to atone for his wasted life. He bequeaths an invaluable gift to Monks Hood Abbey, an ancient monastery set in a lonely corner of the Yorkshire moors. But sin throws a long shadow and corruption crawls in its shade. Strangers come forward and lay claim to the monks' inheritance.

January 1910. A journalist has been killed in a suspicious blaze. Everything points to a group of suffragettes, but the apparent culprit insists she is innocent. When Lady Hardcastle receives a letter from a suffragette requesting her urgent help, the retired spy turned sleuth knows only she stands between an accused young woman and the gallows. Evidence at the scene makes Lizzie Worrel’s innocence difficult to believe, and with the police treating it as an open-and-shut case of arson, Lady Hardcastle faces a barrage of resistance as she tries to dig out the truth.

England, 1920. Lady Eleanor Swift, adventurer extraordinaire and reluctant amateur detective, is taking a break from sleuthing. She’s got much bigger problems: Eleanor has two left feet, nothing to wear and she’s expected at the masked ball at the local manor. Her new beau Lance Langham is the host, so she needs to dazzle. Surrounded by partygoers with painted faces, pirates, priests and enough feathers to drown an ostrich, Eleanor searches for a familiar face. As she follows a familiar pair of long legs up a grand staircase, she’s sure she’s on Lance’s trail. 

Spring, 1921. Lady Eleanor Swift, explorer extraordinaire and accidental sleuth, hasn’t had a vacation since she arrived in England a year ago. So she books into the Grand Hotel in the fashionable resort of Brighton for some fresh air, fish and chips, and, of course, a dip in the ocean. Eleanor is enjoying her view of the waves and trying to find her bathing suit when calamity strikes: A guest has been found dead at her beautiful hotel. The distraught manager, who can’t afford a scandal, asks Eleanor to solve the case as swiftly as possible.

Autumn, 1920. Lady Eleanor Swift, accidental amateur detective and retired explorer, is determined to take a break from investigating murders. So when a local politician dies suddenly at an elegant dinner party at Farrington Manor, she tries her hardest not to listen to the raft of rumors around the village that he might have been poisoned by the fudge. It’s the anniversary of the disappearance of her beloved parents, and she’s promised herself not to get mixed up with any more mysteries. She isn’t sure they’d have approved.  

The London Silver Vaults - for well over a century, the largest collection of silver for sale in the world. It has more locks than the Bank of England and more cameras than a celebrity punch-up. Not somewhere you can murder someone and vanish without a trace - only that's what happened. The disappearing act, the reports of a blinding flash of light and memory loss amongst the witnesses all make this a case for Detective Constable Peter Grant and the Special Assessment Unit.

Winter, 1933. Kitty Underhay is enjoying a restorative break from sleuthing on a visit to her family at Enderley Hall. The only thing marring her peace - aside from the uncomfortable sensation she has of being watched - is the obvious history between her beau, ex-army captain Matthew Bryant and another guest, the beautiful Juliet Vanderstafen. So, when the parish clerk is found dead on her front doorstep, Kitty leaps at the chance of distraction. 

A suspicious accident, a dead man's gun and a lost tomb. Strange events disturb the peace of Lanscombe Park, the magnificent country seat of Lord Godolphin Sinclair....

It is the summer of 2013, and Abigail Kamara has been left to her own devices. This might, by those who know her, be considered a mistake. While her cousin, apprentice wizard and police Constable Peter Grant, is off in the sticks chasing unicorns, Abigail is chasing her own mystery. Teenagers around Hampstead Heath have been going missing, but before the police can get fully engaged, the teens return home - unharmed but vague about where they've been.

Spring, 1909, and Lady Hardcastle, amateur sleuth and all-round eccentric, is enjoying a well-deserved rest. But a week after a trip to the cattle market, Spencer Caradine, a local farmer, turns up dead in the pub, face-down in his beef and mushroom pie. Once again, it is up to Lady Hardcastle and her maid, Florence, to solve the case. Armed with wit and whimsy, not to mention Florence’s mean right hook, the pair set out to discover what really happened and why. Was it poison or just ill luck?

It's 1920, and Christmas is coming. Major Lennox finds a body on his doorstep - why on his doorstep? Was it to do with the Countess? Was it about the ruby necklace? Lennox goes to Melrose Court, home to his uncle, Lord Melrose, to uncover the mystery. But then, the murders begin, and it snows, and it all becomes very complicated.

A centuries-old skeleton is discovered in a lonely Scottish Castle. It wears a crown and hides a curse. Swift, the detective friend of Major Heathcliff Lennox, now lives at Braeburn Castle, and it was he who uncovered the skeleton. As ghosts are heard and treasure-seekers appear, the murders begin. Lennox must go to Braeburn and investigate as Halloween draws near.