Social media was awash with discussion on Sunday evening as BBC police drama Line of Duty returned for a new season.
uch of the conversation following the Series 6 premiere centered on a new acronym for fans to ponder, 'Chis'.
The real-life policing term stands for 'covert human intelligence source', or an informant, but fans of the show are by now well used to creator Jed Mercurio's fondness for code.
Pointless host Richard Osman pondered if the new phrase had a deeper meaning.
"So they're telling us Chis stands for 'Covert Human Intelligence Source'. But what if Chis really stands for 'Clearly H Is Steve'? Makes you think," he wrote on social media.
BBC Breakfast host Dan Walker admitted immediately googling the term.
Radio 1 DJ Melvin Odoom wasn't the only one struggling to keep up with the show's many plot twists.
"Line of Duty was good but if you have a memory like mine you definitely need to watch the recap on YouTube to remember what the hell is going on," he said.
A number of people also noted Enniskillen actor Adrian Dunbar's use of the local phrase "houl your whisht".
"Good to see Fermanagh spake on the nation's stage tonight," Ian Acheson wrote.
Local broadcasting legend Eamonn Holmes admitted he loved the show, but said he often found his attention diverted.
"Going to have to watch on catch up as I get too distracted spotting where they are in Belfast. I'm going for Cavehill Road/ Sunningdale, north Belfast Opening scene - followed by Cregagh, east Belfast. What you think?," he asked his Twitter followers.
Former RUC officer and internet security expert Jim Gamble was critical of one aspect of the show.
He pointed out that a character played by a disabled actor was referred to as "the local oddball", with the episode airing on World Down Syndrome Day.
"Especially on the day that it is but also on any day, the script writer of Line Of Duty needs to reflect on the line referring to a suspect with special needs being referred to as the local odd ball," he wrote.
However, other Twitter users pointed out it was fitting to have the actor appear on the show.
Noted English solicitor Nazir Afzal said the brilliance of the show was that "you trust nobody".
"Everything could be something or nothing, everybody is dodgy/honest depending on what you believe. Then you start questioning what you think you know and who you believe. Well done Jed Mercurio," he said.
Comedian Matt Forde said it was a "brilliant return" for the show.
"History will now show that what eventually saved the country from Covid was the vaccine and Line of Duty Series 6," he said.
Fans were also left reeling after it was revealed Vicky McClure’s DI Kate Fleming has left AC-12.
One fan wrote on Twitter: “Things I’m not happy about.. Kate not being in AC12, Steve wanting to leave AC12 and Ted not being in my tellybox enough.”
Another said: “Can’t handle Steve-mate and Kate-Mate not workin’ together #LineOfDuty #motherofgod.”