The 34th Floor of Nakatomi Plaza was the conference level where high-profile executives of the Nakatomi Corporation, such as Joe Takagi commiserated over their usual day-to-day business matters. It was highly luxuriant, containing a vast array of Asian-style antiquities and a grand hall exhibition of Nakatomi's numerous projects and technological advances found across the globe.
After Hans Gruber and his band of terrorists seized control of Nakatomi Plaza on Christmas Eve, he accompanied Mr. Takagi to the 34th Floor under the guise of making his terrorist demands known to the corporation. Karl and Tony escorted them to the conference room where Theo was already waiting for them. On the way, Hans stopped to admire the various models on display, marveling over both one of Nakatomi Plaza and another of a major bridge project underway in Indonesia. Hans ordered Mr. Takagi into the conference room, revealing to him there of his actual desire to obtain the $640 million in bearer bonds held within the Nakatomi Vault, to which he demanded the access key from Mr. Takagi. Unbeknownst to anyone, John McClane happened upon the group as he tried to sneak past the terrorists, and spied on the meeting from afar. Holding Mr. Takagi at gunpoint, Hans demanded the code from him, but Takagi argued that the code key was only good for the first of their seven locks and therefore useless, which made little difference to Hans who was already aware of this. When Mr. Takagi didn't talk, Hans executed him with a point-blank shot to the head, and John was forced to back off as he knew he was outgunned. Hans then had Takagi's body hidden away, leaving his blood splattered across the boardroom.
After evading Karl, Franco, and Fritz on the rooftop, John retreated back to the 34th Floor to where Takagi was murdered, hoping to signal for the police whom he called to the scene. A single car driven by Sergeant Al Powell showed up, and he proceeded to question Eddie, who was posing as the night guard on the alleged distress call. Frustrated, John began smashing through the window with a chair; James alerted the others to the disturbance and Heinrich, who was busy rigging the C4 on the roof ordered Marco to intercept, following after him. John held up Marco at gunpoint demanding him to surrender, but was forced to defend himself when confronted by Heinrich, who he quickly shot dead. Marco cornered John beneath the conference table and prepared to unload on him as John ran out of cover. Instead, John fired through the table at Marco before he could pull the trigger, killing him as well. When he saw that Powell was leaving the scene, John threw Marco's body out the window onto the hood of Powell's car, causing him to panic and radio for backup as the terrorists fired on him. With this, the LAPD arrived in full force to retake Nakatomi Plaza.
Before fleeing the 34th Floor, John taunted Hans with the news of Marco and Heinrich's deaths and stole Heinrich's bag, which contained the detonators for the bombs on the roof. Karl and his team discovered what McClane had done and returned to defend against the advancing LAPD.
The 34th Floor was likely heavily damaged if not completely destroyed when the rooftop was eventually detonated by Hans.