She was doing well in the polls and Jeremy Corbyn's Labour Party were a mess. After a year of confusion and in-fighting, culminating in a poor result in the Copeland by-election, there was no sign that Labour would hold onto a decent proportion of the seats it currently had.
Buoyed by her support in the right-wing press, Mrs May set forth on the campaign trail, confident of an increased majority for the Tories.
And then something strange started to happen. Even though the press derided him and the poll results were against him, Jeremy Corbyn started to gain popularity. He was failing according to the newspapers and radio reports but he was all over social media. As the interviews and debates began, Theresa May kept out of the way and Corbyn gave speeches to huge crowds.
There were hiccups along the way. Repeated questions about Labour's attitude towards nuclear weapons and Corbyn's relationship with the IRA in the past. Some vagueness from him on Women's Hour about data in the manifesto. But the Tories made worse mistakes. May's refusal to debate with the other party leaders worked against her and Home Secretary Amber Rudd was laughed at on Question Time.
When the exit polls suggested a hung parliament the media went into a frenzy of analysis: were the polls wrong? Was it possible?
Then it happened. Labour got their best result since the Blair years. The Tories had more seats but lost their majority. It was the hung parliament predicted. As Theresa May tried to pull together a coalition and patch up her battered image, Corbyn reflected on the surprise result.
And people started to see him as a potential Prime Minister in waiting. A new hope for the Left.