Lady Rosalind Devine is furious when she learns her brother arranged for a guardian to watch over her while he and his bride are away on their honeymoon. Gabriel Devine knew better than to leave his troublesome sister on her own. After all, Rosalind is prone to meddling, eavesdropping, and matchmaking. The number of suitors hoping to win Rosalind's love also worries her older brother. When Gabriel discovers the gentlemen of London have begun placing a wager on who will win Rosalind, Gabriel appoints a secret guardian to watch his sister's every move. The only thing worse than having a guardian is not knowing his identity. Rosalind is determined to discover who her mysterious guardian is so that she can either charm him into her service or bribe him.

Rosalind believes the ball before her brother's departure will be the perfect opportunity to discover who her guardian is. But when Nicholas Kincaid is announced as the new Marquess Winterbourne, Rosalind is too distracted to find her mysterious protector. Nicholas is her brother's dearest friend who Rosalind has secretly loved for years. After Nicholas is presented as Lord Winterbourne, Rosalind looks on with envy as every single woman attempts to catch his eye. But much to Rosalind's dismay, Nicholas barely acknowledges her presence.

While her brother, Gabriel, is away, Rosalind divides her time between attempting to win Nicholas' heart and finding out who her secret guardian is. After Rosalind begins to grow suspicious of Nicholas' constant presence at her home, she sets a trap and discovers that he is the man assigned as her guardian. Although Rosalind's beauty succeeds in winning Nicholas' heart, he refuses to break his vow to his dearest friend by falling for the woman he was asked to protect.

GUARDING A NOTORIOUS LADY is primarily devoted to Rosalind's search for her secret guardian. Unfortunately, the readers are already aware of who he is leaving zero mystery and very little plot. The main revelation readers have to look forward to is Rosalind's reaction. Fortunately, the characters still make the novel enjoyable. Lady Rosalind's matchmaking reminded me of Jane Austen's Emma. Nicholas' refusal to give into his feelings for Rosalind will also please readers who enjoy a good playing hard to get storyline.