From rivalries to repeats, there'll be a lot on the line when the NHL playoffs begin on Wednesday. Here's a look at some of the storylines to watch. After a historic season, the Tampa Bay Lightning are the easy favourite to hoist the Stanley Cup. The Washington Capitals have scarcely slowed after capturing the Cup last season, but repeat champs are rare in today's NHL. A deep rivalry will be rekindled when the Toronto Maple Leafs face the Boston Bruins on Thursday. The San Jose Sharks may enter the post-season with a whimper if their recent play is any indication. The Carolina Hurricanes are back in the playoffs for the first time since 2009 but will face off against the Capitals in round one. The St. Louis Blues were last in the league on Jan. 3 but went on a mid-season tear, winning 11 games straight from Jan. 23 to Feb. 19. The Vegas Golden Knights made history last year, skating through the playoffs, taking out the L.A. Kings, Sharks and Jets before meeting their match in the Capitals. The Columbus Blue Jackets will be leaning hard on their marquee players to help make history and win a playoff series for the first time in franchise history.