I had an unlikely friendship in my Nanowrimo novel which, while it's not pivotal to the story line, is important to both of the character arcs of my characters. So I began to try to take apart this common trope and find out what exactly how to pull it off convincingly in a story.
(I'm going to use examples from Finding Nemo because it did such a great job with this.)
Marlin and Dory clash partly because Dory is super annoying, but also because Dory’s happy-go-lucky personality conflicts with Marlin’s up-tight chronic anxiety.
In my story my two characters are totally opposite on the Myers Briggs spectrum. That wasn’t intentional; it just happened that way. But giving characters a few similarities can often make them clash even more.
Not only personalities clash, but goals can clash too. Think of Buzz and Woody from Toy Story. They start out the movie trying to get rid of each other because Andy can't have two favourites.
Marlin just wants to get away from Dory. He doesn’t need her around. The movie makers had to make a reason for the two to be together long enough for Marlin to realise he needed Dory’s help. So they made Bruce the shark show up and “invite” them to a party. They have no choice but to be together at this point. The fact that they are both in danger also creates a link between them.
In my story I did the same thing, making both characters on the run from the bad guys. You could also trap the two characters in a room together or even handcuff them together.
When Marlin finds out that Dory can read, he knows that he needs her help to find Nemo. Now there is a greater tie binding them together which keeps them together until they actually reach Sydney. By that time the writers have progressed the relationship to the point that Marlin realises he needs Dory for other reasons as well. But we’re getting there.
This phase of the friendship is found in most buddy love movies. There’s usually a fun and games section where the characters are getting to know each other and finding out not only things they didn’t know about each other, but also things they hadn’t known about themselves.
Marlin discovers that Dory can read. He also discovers a lot of courage he didn’t know he had, when he has to confront sharks and deep sea monsters.
This is where they begin to find out that they are in fact a dynamic duo. They each have strengths and weaknesses that complement the strengths and weaknesses of the other. They begin to discover that they not only need each other in the short run, but in the long run as well, and most importantly, they begin to rely on and trust each other on a subconscious level.
Dory needs Marlin because he helps her remember things, and Marlin needs Dory because she's brave and sometimes surprisingly right in her intuitions.
It shouldn’t be anything too major, but it should be something that comes as a wake up call to one or the other of the characters. While it may cause a rift in the relationship, once that is patched up, it should cement the relationship further because both characters build a deeper level of trust for each other. They have begun to learn how far they can trust each other.
Marlin doesn’t believe Dory when she warns him not to swim over the trench and because of it they are almost killed and Dory is badly injured. Through this event, Marlin learns to trust Dory’s judgement, even if it doesn’t make sense. He also gets some bonus guilt that comes into play later in the story.
It’s important to plant this bit of doubt early on in the story so that it has some time to fester before you bring out the big whammy: a major betrayal or loss.
Give your characters a moment of triumph or simply happiness to share together. This will build their relationship on an emotional level so that they’re not just depending on each other to get their goals; they’re beginning to actually like each other.
Dory and Marlin share several up moments, mostly moments of triumph as they escape various perils of the sea.
At some point the characters need to realise that they actually care about each other. They’re no longer planning to ditch the other character as soon as they no longer have a need for him; they’re friends and they are now trying to protect or save each other. Think of the moment when Buzz and Woody FINALLY start working together. We realise that both of them are actually willing to sacrifice the very goal they started out using the other character to achieve, in order to save the other character.
This can happen and does happen all along through the story, but there needs to be a definite point when the character realises just what the other character has taught him. Marlin realises his controlling nature when he finally has to let go and trust Dory in the whale’s throat. Even though the story is far from over, this moment of revelation shows Marlin just how important Dory has been to him and how much she’s taught him about himself.
How much do they really care about each other? Now’s the time to find out. There may be a point in your story where they decide to break up, as Marlin and Dory do when they are unsuccessful in saving Nemo. There may be a moment of deep and utter betrayal, worse than the plant you put in the story for step six. Or, they may simply decide it’s not worth trying to make things work out.
But you don't want to leave the story here. Make them realise that they can’t walk away from the relationship and show how much they’re willing to sacrifice to save the other one. Marlin has to let Nemo risk being caught so that he can save Dory. His original goal (shielding Nemo from danger) is sacrificed in order to save Dory, and Marlin has to use what he's learned (letting go of control) to get there.
Now you're ready to write an unlikely friendship story. Maybe about a walrus and a carpenter...