In the episode, alien time traveller the Doctor (Jodie Whittaker) brings her human friends – Graham O'Brien (Bradley Walsh), Ryan Sinclair (Tosin Cole), and Yasmin Khan (Mandip Gill) – back to Sheffield, where they discover a serious problem is roaming around the city in the form of giant spiders.
Having returned to Sheffield, the Thirteenth Doctor goes to meet with Yasmin's family alongside Ryan, whilst Graham heads home to grieve over Grace's death.
After Yasmin leaves to pick up her mother, Najia Khan, the Doctor and Ryan encounter arachnologist Dr. Jade McIntyre while trying to meet the family's next door neighbour.
Bradley Walsh, Tosin Cole, and Mandip Gill appear as The Doctor's companions Graham O'Brien, Ryan Sinclair, and Yasmin Khan respectively.
[1] After the premiere episode, "The Woman Who Fell to Earth", was broadcast, it was confirmed that Chris Noth and Shobna Gulati would be among a number of guest actors that would appear in the series.
The critical consensus reads "Creepy, crawly, and chock-full of first-class guest stars, 'Arachnids in the U.K.' feels like a big budget B-movie, providing another delightful romp for Team T.A.R.D.I.S.."[5]