Mrs Mary Dunbar Hewlett (née Kingcome) was born in Clifton, Bristol, Gloucestershire, England on 8 July 1855, later being baptised on 27 July that same year in St Andrew's Church, Clifton.

She was the only daughter of John Kingcome (1829-1880) and Rosa Lloyd Villiers (1818-1903) who were married in Clifton on 9 September 1854. Her father hailed from Devon and was a silk merchant; he died in December 1880. Her mother was born in Covent Garden, London and worked as a milliner and dressmaker. Mary had only one known sibling, her younger brother Henry Frederick (1857-1865). 

Mary first appears on the 1861 census and was, at the time, resident of Belmont House in Clifton and described as the daughter of Anne Birch (b. 1791), who may have been a great-aunt. The 1871 census shows Mary then reunited with her mother Rosa and grandmother Mary Kingcome at the same address and, aged 15, she was described as a scholar. 

Mary was married in Clifton on 14 June 1875 to Frederick Rufford Hewlett (b. 15 May 1847), a draper and native of Plaistow, Essex, and the couple went on to have four children: Francis Rufford Kingcome (1877-1936), Mary Rosa (b. 1878, later Mrs Edwin Adam Villiers), Florence Rufford (1879-1963, later Mrs Edgar Arthur Groves) and Phillip Rufford (b. 1881).

The family appears on the 1881 census living at 11 Kings Hill, Cotham Villa, New Road, Westbury on Trym, Gloucestershire and on the following 1891 census at 4 Christchurch Road, Willesden, Middlesex, the home of Mary's widowed mother Rosa.

Mary was widowed when her husband died in mid-1899 aged 52; she was never remarried and continued to live with her mother, appearing on the 1901 census living at 166 Willesden Lane, Willesden, Middlesex. Her mother later died in 1903. 

Mary's younger son Phillip was a civil engineer and lived and worked in Lucknow, India; she had paid a visit to him and returned to Britain in early 1912 where she visited her daughter Mary Villiers in Lymington, Hampshire before boarding Titanic in Southampton on 10 April 1912 (ticket number 248706 which cost £16) in order to visit her son Francis in Rapid City, South Dakota. 

Mrs Hewlett survived the sinking and was rescued by the Carpathia in lifeboat 13. On the Carpathia  she sent a telegram to London on 18 April at 4.21 pm:

Groves - Avenue - Brondesbury London. Rescued unhurt
Carpathia

Mrs Hewlett was met in New York by her son Francis although he had not received word of her survival and did not meet her coming off Carpathia; she continued to South Dakota for a time before she boarded Laconia in Boston for her return voyage to Britain and arrived in Liverpool on 5 June 1912. Whilst aboard she wrote a letter to a friend:

On Board the Cunard R.M.S.Laconia

May 30th 1912

My dear Marcia 

Now that I have recovered from the nervous breakdown I had after the horrors of the shipwreck, I will try to write you a little about it. 

I was in bed and asleep and did not feel the shock of the collision with the iceberg & no one called me, I awoke & finding the engines had stopped I got out of bed & looked into the alleyway - I saw the steward - he assured me there was no danger & that I need not dress unless I liked then I heard him go to the stewards cabin & say "hurry up" so I got on my under clothes & my fur lined coat & a hat & went on deck & there an officer was ordering people to climb up a ladder on to the upper deck so I went with the crowd & when I reached the top there were eight or ten stewards there who said I must get into a boat that was on the davits - however they insisted & I was put into boat No.13 - with about 50 people - mostly men of the unemployed class & stokers, stewards & cooks - not one real seamean amongst them there were only about 12 women in the boat & no compass, lanterns or water, - when the boat finally reached the water there was this one who understood how to release it from the ropes & so there we were until a knife could be found & the ropes cut in the meantime no 14 boat was descending on the top of us & we had great difficulty in making them stop lowering that boat until we were free - Then we pulled out from the Titanic somehow as the men at the oars did not know how to row - could not keep time & did not know starboard from port!!!

We saw about a mile & a half away before the ship finally went down & then we stayed there in the dark with icebergs all around as the other lifeboats (also without lights) rowing about near us. I had some long letters (I had written to my girls) in my handbag & I gave them to be burned sheet by sheet as signals. The dawn came about 4.30 & then we saw dozens of icebergs & the new moon in a pink haze. It was a most wonderful sight & soon after that, about five o'clock we saw the mast lights of the Carpathia on the horizon -- & then the headlights & then the portholes & then we knew we would be saved. We had to go up a rope ladder on the side of the "Carpathia" (I didn't know how I did it), and then we were taken on board given coffee & brandy - but as our boat was about the sixteenth or seventeenth to arrive all the berths were given away before I reached there & and so had to stay in the Library for the four days and nights before we reached New York -- and there were no brushes or combs to be had - nor tooth brushes as these were all sold in a minute. The Carpathia is a small ship and how she found room & food for seven hundred people besides her own passengers seems marvellous. Of course the scenes on board were very harrowing -- as so many people had lost their dear ones -- there were 150 widows. Thank God -- Jumbo was not with me -- so that I lost only my clothes & presents for my family in America. When I landed in New York my son Frank was not there to meet me - he did not get my letter until after the accident so I had to stay in New York alone for three days until he came. I had no dress on & no luggage, but the people at the hotel were very kind when I said I had been on the Titanic & the housekeeper lent me a nightie & wrapper -- until I could get some things from the shops. I had some money in a little bag on my corsets as well as my best jewellery. So I was very fortunate...."

Mrs Hewlett returned to her son in Lucknow, India and she would spend the rest of her days in that country. 

Mary Dunbar Kingcome Hewlett died following a spell of septicaemia in the Ramsay Hotel in Naini Tal, India of on 9 May 1917 and she was buried the next day in in Kaladhungi Road Cemetery at the foot of the Himalayas. Her probate lists her last address as Clyde Road, Lucknow and her estate, worth £155, 16s was administered to her daughter Florence Groves of Hastings, Sussex.