It's ten years since Tom Hanks first played the dull but exceedingly well-read Robert Langdon in The Da Vinci Code, and seven since he did another lap of art-history orienteering in Angels and Demons.
That time lag might suggest a lack of urgency in getting to Inferno, Hanks' and director Ron Howard's third Dan Brown adaptation. And that maybe even the participants are tired with Brown's historic conspiracy puzzlers.
Langdon, as the business class Indiana Jones, is called on again to be the smartest guy in the room. Albeit in some very nice rooms - for all its tedium, Inferno is a sightseeing treat as it flits from various galleries, churches and palaces in Florence, Venice and Istanbul.
But while the previous films had some pace and felt like there was something at stake in the Christianity versus science mumbo jumbo, this one is leaden in almost every department.
Watching it feels like signing up to a tour group visiting the sites of Brown's less popular works and you're not allowed off the bus.