___Set in 1887 or 1888; The Sign of Four has a complex plot involving service in colonial India, a stolen treasure and a secret pact among four ex-convicts. It presents the detective's drug habit and humanizes him in a way that had not been done in the first novel, A Study in Scarlet. It also introduces Doctor Watson's future wife, Mary Morstan.
"The Secret Adversary"
by Agatha Christie
[UNABRIDGED AUDIOBOOK WITH TEXT]
With jobs thin on the ground Tommy and Tuppence decide to form a partnership and hire themselves out as 'young adventurers, willing to do anything, go anywhere'. When their first assignment, for the sinister Mr Whittington, puts both of them in mortal danger, they have to use all their ingenuity and cunning to save not only their own lives but that of the mysterious 'Jane Finn'.
"The Mirror Crack'd from Side to Side"
by Agatha Christie
[UNABRIDGED AUDIOBOOK WITH TEXT]
One minute, silly Heather Badcock had been gabbling on about her movie idol, the glamorous Marina Gregg. The next, Heather suffered a massive seizure. But who was the deadly poison really intended for?
"Partners in Crime"
by Agatha Christie
[UNABRIDGED AUDIOBOOK WITH TEXT] This title contains six short stories from the Queen of Crime, telling, amongst other things, of Pink Pearls and Sinister Strangers. Tommy and Tuppence Beresford were restless for adventure, so when they were asked to take over Blunt's International Detective Agency, they leapt at the chance. After their triumphant recovery of a pink pearl, intriguing cases kept on coming their way: a stabbing on Sunningdale golf course; cryptic messages in the personal columns of newspapers; and even a box of poisoned chocolates.
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"The Mirror Crack'd from Side to Side" 
