When the redoubtable Sir Horace Stanton-Lacy is ordered to South America on Diplomatic Business he parks his only daughter Sophy with his sister's family, the Ombersleys, in Berkeley Square. Upon her arrival, Sophy is bemused to see her cousins are in a sad tangle.
The heartless and tyrannical Charles is betrothed to a pedantic bluestocking almost as tiresome as himself; Cecilia is besotted with a beautiful but quite feather-brained poet; and Hubert has fallen foul of a money-lender. It looks like the Grand Sophy has arrived just in time to sort them out, but she hasn't reckoned with Charles, the Ombersleys' heir, who has only one thought - to marry her off and rid the family of her meddlesome ways.