Although all the novels in the Spenser series are interrelated to some degree, Sudden Mischief echoes the novels Valediction, The Widening Gyre, and A Catskill Eagle.

In those novels, Susan is estranged from Spenser and struggles with her involvement with Russell Costigan. In Crimson Joy, Spenser's pursuit of a serial killer who was one of Susan's patients, introduced tension into their relationship. However, in Small Vices, the book before Sudden Mischief, Susan and Spenser's love was reaffirmed by Spenser's nearly fatal encounter with the assassin Rugar and by Susan's heroic commitment to helping Spenser recover and rehabilitate himself.