The kids are encouraged not to underestimate the power of destiny. For example, Ted's trip to Chicago. We wonder why the trip is so important - he has an interview at corporate headquarters in chicago. Unfortunately the person at the desk tells he and Robin that the door is shut and she can't get it open.
The woman tells them that everything is up to the captain. He explains he's normally on time but he was in court for jumping a subway turnstile. The phone rings but it's the woman's mother. Ted wonders why he jumped the turnstile to begin with. Robin says it's really Barney's fault and we go back a few months earlier.
Marshall was hobbling around on a broken leg. He feels bad he won't be able to run the marathon and it's a shame he spent all the time training. Barney says training is a waste of time and they make a bet that he can't even finish the race.
The next day they are tracking him via a device on Barney's shoe. They are amazed at how fast he is running and don't think it's him but they caught up to where he was and saw him running. After he finishes the race they tell him that all runners can ride on the subway for free. Later he calls and tells Ted that his legs don't work now. Soon Barney is surrounded by people who rightfully should have his seat but he can't get up and an old woman calls him a douche.
Ted goes to meet Barney at the 86th street station and rushes to see him and jumps the turnstile due to the time crunch and is immediately arrested. Ted goes to inquire about the flight and it turns out it left. They find out there was another flight that would get them to Chicago just on time. They continued to blame Barney but then Ted says Barney would have not run the marathon had Marshall not broken his leg.
We go back a few months to when Marshall decides he is going to run the marathon. After he finds out that liquids are digested faster he blends up pancakes and orange juice and then runs straight for the toilet. Lily tells him (from the Dummy book) that he has to give himself plenty of positive reinforcement and he does including a nice "We Are Marshall" reference. There's advice about rubbing petroleum jelly on rashes and after one long run he does so. When Robin surprises him he slips and breaks his toe.
Robin says she wouldn't have gone into the apartment were it not for Lily. We go back to a wedding dress sale that people need to camp out to get a good spot in the line for the sale. A car alarm goes off and continues to sound five hours later. Robin says they should sing along. It's like that Dane Cook joke. Three hours later Lily vows to live her life diferently. When the guy finally comes and turns his alarm off he is pelted with food. It is the next day that Robin surprises Marshall.
At the door the agent recognizes Robin and they talk about her being a news reporter. Ted says this is all a nightmare. Ted says it all goes back further and remembers finding a 1939 penny on the train - 67 years old, minted during World War II. Ted tells Robin the coin is worth something. He says he'll take her out to dinner for what the penny is worth. Apparently the penny is worth one dollar and fifty cents.
Ted realizes that because of the dinner he saw the sale and because of his seeing the sale none of the other things would have happened. The agent at the gate says there are no extra seats on the plane. She tells him his destiny was not to go to Chicago. It seems good because the person who got the job was relocated to Chicago and if he had been relocated he wouldn't have met the kids' mother. We see him looking lovingly at the person at the altar on their wedding day. Of course we don't see who it is.
-- Gordon Davidescu