When we first meet Peter, Susan, Edmund and Lucy they have been separated
their parents by WW II and sent to live in a strange house in the care of
unfamiliar and unfriendly adults.
In 'Prince Caspian' the title character is an orphaned heir on the run from
evil Uncle who has usurped his throne.
In 'Voyage of the Dawn Treader' Edmund and Lucy are staying with their least
favorite aunt and uncle and nasty cousin Eustace while their parents are out
of the country.
In 'The Horse and His Boy' Shasta is the unwanted adopted child of an abusive
fisherman who intends to sell him into slavery. And Aravis is escaping from her
wicked stepmother and a forced marriage to an old but rich man.
In 'The Silver Chair' Jill and Eustace are victims of the school bullies at
their 'progressive' boarding school.
And of course poor Digory is living with his aunt and crazy wizard Uncle
because his father is in India and his mother is dying.
None of them are exactly enjoying a childhood 'free from care' and plunging
into Narnia only puts them in more jeopardy.