(Ron P. Jaffe | CBS)

It’s a strategy that’s worked for years. Throw the same funny people into different situations every week and hilarity ensues. Luckily, “How I Met Your Mother” knows how to follow a formula. If you’re not family with HIMYM, the show is about its central character, Ted (Josh Radner), and how he – you guess it – met the mother of his children.

Spending four years trying to reveal the identity of one woman could be about as interesting as watching water boil. But that is why HIMYM is an ensemble comedy. Ted is the heartfelt architect searching for his one true love. Marshall (Jason Segel) and Lily (Allison Hannigan) have been together since college, but have a relationship as stale as freshly baked bread. Barney (Niel Patrick Harris) is the suit-wearing cad with a secret heart of gold. And Robin (Cobie Smulders), the Canadian ex-pop star who can’t find her path, rounds out the group.

In last May’s season finale, we learned that Ted was going to become an architecture professor at Columbia. And more importantly, we saw Robin and Barney, who had spent more than a year in will-they-or-won’t-they relationship limbo, make out passionately. All summer, viewers were left to wonder if they would get together.

Monday’s season five premiere, “Definitions,” was pretty simple. Ted nervously begins his teaching career as an architecture professor at Columbia. He awkwardly tries out a few teaching styles to see what kind of professor he should be. Unfortunately for Ted, nothing works. Not because he’s a bad teacher, but because he walked into the wrong lecture hall. Once Ted realizes this, he runs to the right architecture classroom. When he arrives, he has lost his jitters and becomes an awesome professor.

Meanwhile, Robin and Barney had spent the summer hooking up secretly, because they were not quite ready to define their relationship. Lily was devastated when she learned they weren’t dating, so when she found out that RoBarney were actually still together, she takes matters into her own hands. Lily locks the clandestine couple in Robin’s room and, in the morning, refuses to let them out until they have “the” relationship talk. Barney and Robin eventually decide to lie about being a couple, just so they can escape. As the episode ends, it dawns on Lily, Marshall, and Ted that Robin and Barney are actually falling in love, as much as they try to resist.

While the main plot is pretty funny, the genius of “How I Met Your Mother” lies in the little moments. Marshall gives Ted a fedora and whip to start off his new job, hoping that Ted could channel Marshall’s favorite professor, Dr. Indiana Jones. In one scene, Ted and Barney flashback to a conversation they had in their favorite bar years ago on tuxedo night where they discuss how the rules that apply to gremlins (i.e. never feed them after midnight), also apply to women. The utter randomness of this show makes it a joy to watch. There are a few utterly awkward scenes per episode that also spice up the show. In my favorite moment from “Definitions,” Ted wakes up from a nightmare to find Barney standing beside his bed. Ted starts to explain his dream, not even questioning why Barney is in his room, only to find his friend looking for condoms.

This was an extremely promising season premiere. It will be interesting to see if the Robin-Barney relationship can last without the show losing any quality. I’m more interested in how this new relationship will change the dynamic within the group of friends. Although the characters in “How I Met Your Mother” have their own lives, this show will always be about how Ted, Barney, Robin, Marshall, and Lily interact. After four years, the writers know and love the characters they have created, which makes for an amazing series. With any luck, “Definitions” will be the start of season five’s winning streak, and this season is going to be legen…wait for it…dary!

“How I Met Your Mother” is on CBS, Monday’s at 7 p.m.