Starting a movie is easy, ending a movie is hard, and finding out how to get there is even harder. If you’re ever having trouble along the way, consider taking a step back and looking at your “b” plots. More movies end with a “b” story than you might think. Let’s look at a few famous examples, and see how they managed to pull this off.
Let’s start with a fun example. One of the best moments in Back to the Future is all the unexpected changes Marty made to his own future: His siblings are now successful, he has a sweet new car and Biff Tannen himself has become a household maid. These are all side effects of Marty’s “a” plot, but established as “b” stories from the beginning. It’s not unusual for the “a” plot to effect side stories, Lord of the Rings ends with at least five of them. The stronger the “a” plot, the greater it’s affect will be on the rest of the story.
Sometimes the “b” plot doesn’t even need to be significant. The 2003 version of Freaky Friday ends with two side characters—the little brother and the grandfather—in an argument that’s similar to movie’s inciting incident. It doesn’t amount to anything, it doesn’t change the main story arc, but it’s a fun teaser that leaves the audience with a fun laugh before the credits roll. This is a popular way to end comedies.
Sometimes the “b” story we end on isn’t even the conclusion, sometimes it’s only there to carry us into the next movie. At the end of Lord of the Rings: The Two Towers, Gollum vows to kill Frodo and Sam…and then the movie ends. Revenge is a common motivation for these “b” plots: A minor character emerges from the rubble where the antagonist was destroyed, vowing to fulfill what the villain began. However, revenge isn’t always the motivator. A lot of the early Marvel movies ended on the same “b” plot: Nick Fury assembling a team of Earth’s mightiest heroes.
These can almost be considered a “victory lap” for our hero. They accomplished their goals, they have everything they need, but there’s one more thing that needs to be done. In Hot Rod, this “one thing” was to beat his stepdad in a fight. After Rod pays for his stepdad’s heart surgery (the “a” plot) all that’s left is to beat him in a fight. This “b” plot is a little ridiculous, but after everything they had to go through to get there, it’s like having your cake and eating it too. Remember those bullies who made fun of our scrawny protagonist way back on page five? Now that he’s bulked up, got the girl and saved the day, let's go back and pay those bullies a visit.
Grab some Kleenexes for this one. Remember Up? That ended on a “b” story. Russell wanted to earn his “assisting the elderly” badge, and in doing so he also helped Carl accomplish the “a” plot by reaching Paradise Falls. However, Russell unexpectedly encounters one final obstacle: he doesn’t have a father to help him receive the badge. Well guess what? Carl and his wife could never conceive. This gives Carl one final opportunity to do the things he and his wife could never do, thus fulfilling his “a” plot in a way he never expected.
Admit it, we all love a good romance “b” story. Even the most masculine men tear up a bit when Leia loses Han Solo to the carbonite chambers. Love stories have a satisfying completeness to them, which is why so many movies end on a romantic note even if the movie isn’t necessarily “romantic.” We don’t cut the film after King Kong falls to his death; first we need to see the sailor come to Fay Wray’s rescue. After Rocky goes the distance with Apollo Creed, he doesn’t feel complete until he finds Adrian in the crowd. In a lot of these cases, the romantic “b” story ends up being what the protagonists subconsciously wanted all along.
This can be a very powerful way of ending your story. At the end of The Princess Bride, we don’t close on Westley and Princess Buttercup riding into the sunset. Instead we watch as the grandfather, book in hand, closes the door to his grandson’s bedroom. When his grandson asks him if he’ll read the story again, he replies “As you wish.” This not only resolves their jaded relationship—which was a “b” story from the very beginning—but it helps to strengthen the theme of true love by reiterating the very phrase Westley would say to Buttercup. “B” stories should often reflect the struggles of the “a” plot to some extent. In Home Alone, Old Man Marley shared family issues just as Kevin did. That’s why we don’t end the movie on Kevin’s resolution, but rather the old man’s. We get to see the same themes from Kevin’s life play out to a deeper extent.