The performances are all first-rate, so much so that they help the audience overcome very minor skepticism when events in Tony Basgallop's script feel a bit too convenient to be entirely credible.
It's such a bravura, tightly wound performance--played with restrained intensity by the kind of star seldom featured on American TV--as to keep one glued to the show right up until its slightly anticlimactic, disappointing payoff.
The story ends with a final, not quite believable, flourish on John's part, but Mr. Mackintosh carries it off, riding comfortably above his middling material.