Waltz and Lucy Liu lead this tale of an assassin grudgingly mentoring a younger up-and-comer, but their strong turns can’t fire up the ho-hum story

Action legend Simon West has put together a pretty moderate comedy-thriller with screenwriter Greg Johnson; the collective star power in its (undoubtedly) impressive cast isn’t quite strong enough to make it come alive. It is set in Belfast and Northern Ireland — perhaps because of production funding requirements. There is a slightly weird moment in which Lucy Liu’s character, speaking from a bar in London’s Soho, says wistfully of Belfast: “I’ve always wanted to go there … it’s got a great music scene.” Perfectly true, of course, but there is something rather autopilot about the way she delivers the line.

Christoph Waltz plays an ageing and dissolute hitman called Danny Dolinski whose trigger finger is seizing up with arthritis, so his...