"It was a letter they got from a minister they knew in Leeds, where they came from originally.
"The minister came out to New Zealand, and heard of the plight the family had got into in India.
"He suggested they come out to Whanganui and set themselves up here, and that's what they did."
A wealthy man on arrival, Mr Powell bought property in Whanganui and set up shop as a merchant and auctioneer.
He established a firm Powell, Son and Co. and expanded into shipping and commission agents.
He married again, to Ellen Porter, and on the same day his daughter married David Porter, Ellen's brother.
David Porter was author John Ewan's great-grandfather, making the man himself, Thomas, Ewan's great-great-grandfather.
Mr Powell helped build a new church, chaired a number of committees, and was a leading force in preventing Whanganui from breaking away from the Wellington province it was part of.
His status as an intelligent and well-spoken man led to him being recognised as the chairman of many public meetings in the city from shortly after his arrival through to the 1870s, when his health started to decline.
He was deputy sheriff of Whanganui for a number of years, and was a Justice of the Peace, before dying in 1876 aged 69.
Ewan said he managed to pull the history together from a number of sources, including diaries and letters which were saved by relatives.
"Anybody interested in Whanganui, in general terms, would probably be interested in hearing about people who were there at the time," Mr Ewan said.
"It's really about how the family came to be in Whanganui, settling, and the things they did to help Whanganui be established as a town."
Accidental Immigrants will be in bookstores from August, or can be ordered from Chateau Publishing, PO Box 3523, P O Box 3523, Richmond, Nelson, 7050.