Future Ted says there's a fine line between a true story and a complete lie. For example, Barney convinces a woman that he is Neil Armstrong. Robin comes in and tells everyone that she hates her job and we see the last bad interview she had. Ted volunteers to go on her show and explains that he is recreating the Empire State Building in a smaller scale for a recreation of the skyline.
Marshall says that he got mugged when he was walking in the park and Robin suggests that they borrow her gun. Robin says that she won't it change her and then we see her at the firing range. Robin asks to buy a gun and Marshall says more injuries happen because of a gun than they protect.
Marshall says that the story wasn't exactly accurate. In fact, he was mugged by a monkey in Central Park. Everyone teases him about this. Marshall talks about how people get mugged by monkeys regularly. Robin asks Marshall to come and tell the story on television and he says he will if she won't make a joke of it.
Marshall soon reveals to Ted and Barney that he wasn't mugged by a monkey. He says he didn't want Lily to buy a gun and so he made up the story. Neither Ted nor Barney can tell if he's being truthful. Soon Marshall takes it back again and says that he was nervous and really was mugged by a monkey.
On the show, Marshall goes back and forth between saying he was telling the truth and finally decides he is going to go to bed -- so we never find out the truth. Fortunately, Ted is there with his model and they start to talk about that when the monkey crawls up on the model with a stolen doll. Weirdest ending ever.