'The Flash' season 6 episode 18 spoilers: 'Pay The Piper'

"The Flash" Season 6 returned this Tuesday with highly anticipated episode 17 focussing on the Mirror Iris storyline bringing it a step closer to the climax when Barry Allen finds out the truth. Next week, The CW series features an exciting new episode wherein Barry Allen faces his biggest challenge yet when his former partner Godspeed returns to Central City.

[Spoiler alert! This article contains spoilers from "The Flash" season 6 episode 18. Do not read further if you don't wish to learn more about it.]

The eighteenth episode of the sixth season of "The Flash" is titled "Pay The Piper" and it is a big one. As the title suggests, along with Godspeed, fans will see the return of Hartley Rathaway, also known as Pied Piper.

According to the official synopsis (via Spoiler TV) for the next chapter of the series when the former detective partner of Barry Allen and now an enemy returns to Central City, the scarlet speedster is forced to turn Pied Piper to help stop Godspeed. However, The Flash is in for a surprise when he realises that things between Pied Piper and him are not the same anymore since the events of Crisis on Infinite Earths.

Elsewhere, the show continues to focus on Mirrorverse wherein Iris is still trapped. In the upcoming segment, Iris plans her escape, but will she be able to make it to the real world. With Eva gone, will Iris finally find her way out?

The promo video episode 18 gives a glimpse of the havoc Godspeed causes in Central City. With weakened powers, The Flash is certainly going to need help to tackle the villain. Meanwhile, Cisco tries to stop Barry from putting himself at risk, but there is no way Barry will let his city burn. Unfortunately, he is left weak and clamouring by the white speedster in a jiffy.

"The Flash" season 6 episode 18 airs Tuesday, May 5 on The CW.