There is always 1 open and they rotate the 24 hour opening between the 4 or 5 in the town centre. Its always in the chron although if you are dying, the wicker chemist in sheff is 24 hour. It might save your life. Check before setting off though.
Pharmacist at Tesco's at Wath? It's a 24 hour store, but I don't know about the chemist. Give them a call.
If you are dying wouldn't a trip to the hospital be the best bet rather than trying to find a chemist?