She surprises Sherlock with her knowledge and insight into his character .
Rosamund Mary Elizabeth Morstan ( Amanda Abbington ) is a former assassin and a part - time nurse in John 's practice whom he met following the apparent death of Sherlock .
She surprises Sherlock with her knowledge and insight into Sherlock 's character .
Rosamund Mary Elizabeth Morstan ( Amanda Abbington ) is a former assassin and a part - time nurse in John 's practice whom he met following the apparent death of Sherlock .