Dan Brown's The Lost Symbol premieres Thursday, Sept.

The premiere of The Lost Symbol, based on the third book in Dan Brown's best-selling Robert Langdon symbologist series, is an earnest but half-cooked puzzler featuring capable, amiable leads and a clunky clockwork plot that offers few surprises.

Reminiscent of Indiana Jones and the Last Crusade, it's a loved one that prods Langdon into action, forcing him to uncover a rumored ancient portal that leads to unlimited knowledge and power.

focused instead of some of Brown's more globe-trotting treks, The Lost Symbol is a dive into Masonic mumbo-jumbo in which everyone will learn a valuable lesson about tinkering with the unknown and probing the past.

Nothing in The Lost Symbol is meant to crack molds or rattle cages, but if you're looking to turn off your brain for a bit while a few "smart" characters spout off smart things, it's fine entry-level intrigue.