In August 2017, Liverpool reached an agreement with RB Leipzig to sign their highly rated midfielder Naby Keita in a deal that would go through the following summer.
But while Keita stayed in Germany for a year, the hype train did not wait for him, crossing the English Channel and heading for Merseyside.
Every game Keita played for Leipzig and Guinea became the subject of anticipation and attention, every goal he scored or assist he made (or red card he earned) shared on Liverpool forums and social media. His virtues were extolled, his praises sung, his arrival hotly anticipated. The hype train gathered pace.
The result was that by the time Keita actually did make his debut, he had a lot to live up to. He had been built up into this messianic figure who would be to Liverpool's midfield what Virgil van Dijk had been to the defence - a calming presence who would make every player around him 20% better. And he would also be the final key to Liverpool's title challenge.
The even more remarkable thing was that Keita's debut did live up to the expectation. He was imperious against West Ham on the opening day of the season, dictating the tempo of the play in a manner Anfield had not seen from a midfielder (whisper it) since Steven Gerrard. More passengers crowded onto the hype train.
Perhaps weighed down by these new arrivals, the train's progress slowed to a steady crawl. Keita's performances in subsequent weeks against Crystal Palace, Brighton and Tottenham were competent but unspectacular displays, more reminiscent of Jordan Henderson than Steven Gerrard. And you don't need more than one Jordan Henderson.
A combination of injuries and indifferent form have seen Keita make just one Premier League start since that win at Wembley. Three months into the season, his fate is still in limbo. He hasn't shone like Shaqiri or flopped like Fabinho. The hype train is in stasis, waiting for the all-clear to steam ahead, or the red light to disembark.
Even though Keita has not yet been the final piece of the puzzle for Liverpool, the jigsaw is much closer to completion than it was last season. Jurgen Klopp's team are just two points behind Premier League leaders Manchester City and well in contention for a title push.
Not that anybody seems to believe they can do it. While City are winning every match at a canter, Liverpool are making hard work of it. Results have improved, but performances have not, and the common lament of every poor performance is that Liverpool are getting overrun in midfield.
Their defence is one of the best in the league now. Their front three, despite struggling to find its rhythm this season, is one of the best in the world. Alisson has solved the goalkeeping crisis. Only the midfield remains. In previous seasons, perhaps three out of four would be enough. Against the behemoth of Manchester City, only perfection will do.
Liverpool need a midfield enforcer. James Milner, Georginio Wijnaldum and Xherdan Shaqiri are all very important players for Liverpool, but none of them are that. Jordan Henderson can be on his day, but those days are few and far between. Fabinho hasn't been able to adapt to the English game.
It has to be Keita. The 23-year-old's lack of goals and assists is a concern, but his lack of bookings is arguably a more telling sign of what's wrong. Last season, Keita was booked nine times and sent off three times. This season, one yellow card in the EFL Cup.
Obviously Liverpool don't want him to get suspended, but they don't want him to lose that edge to his game either. Steven Gerrard was sent off plenty of times in the early years of his career, but it made him a better player. Once he learned where to draw the line, he was almost unstoppable.
Sadio Mane has tried stoking the fires in the engine room of the stationary hype train, but only Keita can get it in motion. He must lose his inhibitions and become the Gerrard-esque figure that he was destined to be. If that means a few crunching tackles and a few yellow cards, so be it. Whatever it takes to get the wheels turning.
Keita can still be the player Liverpool fans hoped he would be, but he cannot do it from the back seat. He must enter the driver's cabin, take the wheel, and plot a route towards the promised land.