Bern is the de facto capital of Switzerland.
On December 31, 1999, Tony Stark was invited to Bern in order to give a lecture on integrated circuits as the head speaker at the Bern 2000. He was able to give his lecture despite being heavily drunk, later defined as being both “edifying” and “unintelligible”, depending on the asked person.
Having finished the lectures, Stark attended an ensuing party, where he flirted with Maya Hansen while his bodyguard, Happy Hogan, tried to keep people from approaching him. Before Stark left, Ho Yinsen greeted and introduced him to Doctor Wu, a Chinese cardiologist and their guest in Bern. Stark mocked both of them due to his drunken state.
Stark and Hansen were later approached by Aldrich Killian, founder of a privately-funded think tank called Advanced Idea Mechanics, or A.I.M., and a great admirer of Stark’s work. Killian snuck into their elevator and revealed that he was very interested in Hansen's research as well, offering to recruit her into A.I.M..
To get away from Killian, Stark lied to him and told him to wait on the roof of the building, and he would join up after taking a quick drink. Killian believed Stark and waited for him at the roof until the celebrations for the New Year commenced, causing him to realize Stark was not going to come. Killian considered suicide, but he realized that nobody knew he was even there, which made him realize that anonymity was the rule he would follow to achieve his goals.
Stark reviewed Hansen's Extremis project, which intended to access the area of the brain responsible for repairs and healing in order to chemically recode it. Hogan touched one of the plants serving as test subjects for Extremis, and breaking one of its branches activated the Extremis-induced regeneration. Stark and Hansen entered her bedroom and while she explained possible applications for Extremis, such as disease prevention or even limb regrowth, Stark continued flirting with her.
Hansen’s plant exploded, as it was one of the possible side effects of the use of Extremis, and Hogan rushed to protect his boss, putting him in an embarrassing position. At that moment, the guests gathered in the building started shouting to celebrate the New Year that arrived.
The following morning post-sex, Stark left Bern without saying goodbye to Hansen, just leaving her a note while she was working.