The happiest words in sports will be called out Monday afternoon, when the Washington Nationals begin their season against the Miami Marlins: “Play ball!” The beginning of the Major League Baseball season, with each team’s 162 games stretching over more than six months, is like opening a big adventure book you have been dying to read. The Nats’ season, like any great ad­ven­ture story, begins with our heroes on a quest. In this story, the players are on a quest to win World Series rings. You know there will be plenty of ups and downs and twists and turns. The big question is: Will the story have a happy ending?

Let’s look at some of the main characters in the Nats’ World Series saga.

Bryce Harper: Last season’s teenage sensation is now 20 years old. Nats fans are wondering whether Harper can be even better than last year, when he smashed 22 home runs and was the National League rookie of the year. Why not? Harper is more experienced with a big-league season under his belt. He has been hitting over .400 (that’s an amazing four hits for every 10 at-bats) in spring training games in Florida. I’m looking for him to have a breakout sophomore season.

Stephen Strasburg: Last year, the Nats shut down their hard-throwing right-hander in early September. He had pitched only 159 innings, but the team didn’t want to risk a repeat injury to his throwing arm. Well, Strasburg is back and should be ready to pitch a full season. Expect him to improve on last year’s record of 15 wins and six losses. The Nats’ starting pitching should be sensational. In addition to Strasburg, the team has Gio Gonzalez (21-8 last season) and Jordan Zimmermann (12-8).

Drew Storen: The 25-year-old reliever was the poor guy who gave up four runs in the ninth inning in the Nats’ final, heartbreaking 9-7 loss to the St. Louis Cardinals in the National League playoffs. Can Storen forget about that disappointment and bounce back? Time will tell. But any kid who has made a mistake in a big game should be rooting big-time for Storen.

Ryan Zimmerman: The Nats’ third baseman has been the team’s best player for years. But he is coming back from shoulder surgery and is learning how to throw all over again. Nats fans will hold their breath every time Zimmerman throws to first base. Still, he should be a big part of a power-packed lineup. Jayson Werth, Adam LaRoche, Ian Desmond and Danny Espinosa are all back and swinging hard for the team. They should put plenty of runs on the scoreboard.

So will it be a happy ending or another sad ending for the Nationals? The first chapter will be written Monday.

Fred Bowen is the author of 19 sports books for kids. His latest baseball book, “Perfect Game,” has just been published.