The seven deadly sins were doing their own thing. Escanor and Merlin were talking, Meliodas and Ban were drinking beer, Elizabeth, Diane and Gowther were in the uniform of the boar hat tavern, King was just sleeping on his spirit spears pillow form. It was all going very well, until Meliodas spoke up on his usual cheerful and determined voice

Meliodas: "We need to find the last sin. They were last seen in Liones when they got in prison a few months ago. So let's head there!"

King spoke up on his usual bored tone

King: "Are you sure they would just... let themself get in prison? I mean... theyre pretty powerful."

Gowther spoke up in his usual emotionless voice

Gowther: "It's rather suspicious that they would get prisoned. After all, even Merlins spells don't work on them."

Meliodas: "That's true! I've seen them go a lot. It's most likely they would just wait there for us. So lets go!"

You're the 8th sin, continue the story however you'd like! And have fun!