John Wilk, played by Reeves, is a hit-man who, against all odds, managed to get out of the business alive and relatively happy. In this, John Wilk shares a provenance with movies like Assassins with Sylvester Stallone and Antonio Banderas, in my view the very best of this genre, in which there's of course always something to get the retired assassin drawn back in.
In Wick's case, it's a double punch. His wife, whose love got him to leave the business, dies of natural causes. She arranged to send him a sweet little puppy to keep him company after she's gone. But the headstrong son of a Russian mob boss makes the mistake of cruelly killing the puppy when stealing the keys to Reeves' car.
The death of the puppy was a highly effective and moving scene. It certainly made me want to bring those bad guys to justice, and it was the motivation that set Wick back to his lifetime profession. When the dog killer wonders to Wick and others why Wick is so upset about the puppy's death - "it's just a fucking dog" - we know, having witnessed its killing and what happened with Wick and the puppy before that, why that little puppy was so much more.
The action is great, even though there were a couple of easy shots that Wick missed, in service of the plot, and there were a couple of holes in the plots logic, too. But, on the other hand, the supporting cast was outstanding, including Lance Reddick of The Wire, Lost, and Fringe fame, who's always good to see on the screen, and Willem Dafoe as another hit man.
If the Russian mob, bigger than life killers, and hotels for assassins with rules of the house that must be followed if you don't want to be killed yourself, take a 90-minute break and check out this fine movie.