The series follows teacher Laura Nielson (Joanne Froggatt) who goes on a date with an attractive doctor, Andrew Earlham (Ioan Gruffudd).
The morning after, Laura accuses Andrew of date raping her, but he insists that they had consensual sex.
After skilfully wrong footing the audience for weeks, episode three revealed that Andrew was in fact the liar.
This week’s episode (the fourth) saw Laura travel to Edinburgh to uncover the truth behind the doctor’s wife’s death.
Viewers were shocked when Andrew crept into DI Vanessa Harmon’s flat after spiking her drink.
The next episode will see Laura’s mission to bring Andrew to justice while she recruits his son Tom in on her plan.
As the intense thriller continues, many fans are starting to wonder how many episodes are left.
Liar is a six part series just two episodes left so viewers have another two weeks to wait until the finale.
The drama, written by Bafta winners Harry and Jack Williams, airs on Mondays at 9pm on ITV. Previous episodes are available to stream on the ITV Hub.
The penultimate episode, titled ‘Check Mate’, will air on Monday October.
Episode six, titled ‘The Marshes’ will air on 16 October.
Will there be another season?
The show has already had a big impact on audiences with ITV bosses already making plans for a second season.
Liar has been commissioned for a second series following a rave of reviews.
TV insiders have revealed that ITV are hoping the drama will become the new Broadchurch in terms of success.
A show source said: “The vision is already there for this to continue beyond series one.”