Still eluding her older brothers Sherlock and Mycroft, 14-year-old Enola Holmes continues the search for her disappeared mother while solving mysteries in Victoria's London. Investigating her most perplexing case yet, Enola comes to the aid of a past acquaintance. Rushing off the street after bumping into Mycroft, Enola finds herself in the company of a familiar young lady. Enola quickly recognizes Lady Cecily Alistair, but cannot place the two older women accompanying her. When Lady Cecily begins communicating via coded fan messages, Enola realizes there is trouble. After further digging, Enola discovers Cecily is being forced to marry a dreadful cousin. With time running out, Enola knows she will need Sherlock's help—but his aid could come at the cost of her freedom.