A week later her body was found in a suitcase buried in a shallow grave in the bush in West Auckland.
The accused says Millane's death was an accident, the result of a terrible mishap during a rough or violent sexual act.
But the Crown says he murdered Millane, and then coldly and calculatingly disposed her body and tried to cover up his actions.
During the first week of the trial, shocking evidence about the alleged murder was revealed.
In court to hear each graphic and gruesome point were Millane's parents, David and Gillian.
Monday - a jury selected
Justice Simon Moore opened proceedings in courtroom 11 at the High Court precinct in Auckland.
A jury of seven women and five men are selected and the judge outlines their task, and issues a warning about not conducting their own research or reading, watching or listening to any media coverage of the case.
He introduces the lawyers to the jury, starting with Crown Solicitor Brian Dickey, joined by prosecutors Robin McCoubrey and Litia Tuiburelevu.
The defence is led by Ian Brookie, who is joined by Ron Mansfield and Claire Farquhar.
The jury are then dismissed and told to return to court on Wednesday.
Wednesday - the evidence begins
McCoubrey delivers the Crown's opening address, detailing the case against the murder accused.
For the first time, the jury - and the public - hear details of the hours leading up to Millane's death, how she was allegedly strangled, what the accused allegedly did to dispose of her body and his alleged attempts to cover his tracks.
Brookie also speaks to the jury.
He says the accused admits being with Millane when she died and burying her body, enclosed in a suitcase, in a shallow grave in the Waitākere Ranges.
But he says Millane's death, put simply, was an accident and not murder.
A statement from Millane's father was the first piece of Crown evidence.
Read to the court by McCoubrey, while David Millane sat in the public gallery with his wife, it described how his only daughter was living her dream of a travelling around the world.
The footage, taken from multiple cameras around the central city, shows the pair meeting at SkyCity and drinking at various bars.
They had connected on dating app Tinder and met for the first time that night, drinking cocktails, beers, ciders and tequila shots before going to the CityLife hotel where the accused lived at the time.
The Crown also detail what the accused did after they believe he strangled his date to death.
He watched numerous pornographic videos, took intimate photos of a woman believed to be Millane, Googled the Waitākere Ranges, "hottest fire", whether there were flesh eating birds or vultures in New Zealand and where to buy suitcases.
He then went and purchased a suitcase and cleaning products, put Millane in the former and used the latter to try and clean up the scene of the alleged crime.
This evidence started on Thursday afternoon with police outlining what forensic testing was done in the accused's apartment including the use of Luminol to identify the presence of blood in the room.
The chemical can show traces of blood even when an area has been cleaned.
ESR forensic scientist Dianne Crenfeldt also told the court she found what was "probable blood" in the apartment.
Turlough Thomas-Stone said some of the blood found in the room was 500,000 million times more likely to be Millane's than another woman's.
The trial is scheduled for five weeks but would likely finish sooner, Justice Moore told the jury.
Next week the court will hear more evidence from Crown witnesses.