This is a companion to Hardings Luck,so read both of them if you can.If not,this is wonderful by itself.
Edred and Elfrida find a way to go back in time by putting on clothes from a different era.They meet their cousin Dickie while in the past-but why does he have a bill from their time in his pocket?
This gets very exciting and can be a bit scary,(Edred and Elfrida are imprisoned in the Tower for treason at one point!)but of course it all turns out right,if a bit improbable,in the end.
This is a smashing read and if you read the 2 books together you will see why E.Nesbit is still so popular today.