A modernised version of the legend of Rasputin, Harlequin follows an up-and-coming politician, Nick Rast, whose son Alex is ill with leukemia. Into Rast's life comes a mysterious faith healer, Gregory Wolfe: Wolfe seemingly cures Alex, and Rast's wife Sandy falls in love with the mysterious stranger. But Rast's colleagues and enemies both mis-trust Wolfe's influence and crave his power.
The Rast family (whose surname is 'tsar' backwards) share first names with the Romanovs: Nick (Nicholas II), Sandy (Alexandra Feodorovna/ Alix of Hesse), and Alex (Alexei Nikolaevich). Similarly, Gregory Wolfe is named for Grigori Rasputin.