In essence, England have five days to solve the mystery of Mitchell Johnson and save the Ashes.
Since Johnson has himself been trying for almost 30 years and appears to be as puzzled now as he was when he started it may not be enough.
Sherlock Holmes could probably unlock it, but a travelling private detective is one of the few backroom roles unfilled in the English entourage. What an oversight that could prove to be come the first week of January.
Johnson is the most enigmatic cricketer in the world. He did not level the series single-handedly in Perth on Sunday but his intervention suddenly made a deadbeat Australia realise what they were made of.
They went to their homes spread all over Australia yesterday but they will gather in Melbourne on Christmas Eve as a team repaired in body and more importantly in soul.
It said a great deal about the importance of certain individuals in a team game. In the first Test at Brisbane, Johnson turned in an exhibition of stunning inadequacy and it dragged Australia down with him.
Dropped for the second match in Adelaide, they were hopeless. It was a prime example of can't live with him, can't live without him. And then at Perth came a confluence of circumstances which make sport so alluring.
Johnson had undoubtedly worked on his untrustworthy action, trying to make sure that his arm was in the same place from one ball to the next.
The wind blew in a certain direction, the pitch had pace, Johnson made runs in Australia's innings which swelled his fragile confidence.
It was evident in the two late overs he bowled at England on the first night that he had suddenly rediscovered the ability to swing the ball.
This was something that he had been unable to do for 18 months and which England had never witnessed.
And then bang. On Friday morning he was irresistible. Statistically, his 6 for 38 was only the 415th-equal best innings analysis in Test matches, but it was much more significant than that.
There is however, another bowler whose influence on the destiny of the Ashes might be paramount.
Graeme Swann remains the best spin bowler in the world but he has been greeted in Australia with two pitches on which it has been difficult, bordering on impossible, for him to operate — Brisbane and Perth.
Almost as crucially, Australia in general, and Mike Hussey in particular, are trying to hit him out of the attack and so far succeeding all too well.
Swann bowled only nine overs of the 86 that Australia faced in their second innings in Perth and the suspicion could be formed that England were actually protecting him for battles to come.
How Swann responds now is much more important than the fact he finished outside the top three in the BBC Sports Personality of the Year.
Andy Flower, England's coach, was not minded to talk Johnson up too much yesterday for two reasons. The first is that if he bowls like it again, England's Ashes dreams will be done. The second is that Johnson may not bowl like that again.
Australia may like a pitch at Melbourne to replicate that at Perth but they can go whistle. It will not be possible.
Added to which Johnson may easily lose his radar again. His arm, which has to stay low for him to be at his most threatening, is a moveable feast.
When he said he was not actually trying to swing it in Perth he had to believed. It is a force of nature.
Flower said: “It really cost us in this game, that burst of wickets from Johnson and us not handling the left-arm swing as well as we could have or should have.
That was in the first innings when we were on the verge of settling into a groove against them and that is an area that has got to get better.
He swung the ball from the first ball and we didn't deal with it as skilfully as we should have.”
But if he swings like that again at that pace and so late England may not be able to deal with it. Some bowlers are like that.