This is the 12435th most frequent Turkish word.
hikayelerini
"Her/His/Their stories."
The word 'hikayelerini' is in the accusative plural form, indicating 'their stories' being referred to as the direct object of the verb 'anlattı' (told).
Arkadaşım bana hikayelerini anlattı.
My friend told me their stories.
Here, 'hikayelerini' also in the accusative plural form, represents 'their stories', this time as part of the predicate describing the act of listening as enjoyable.
Hikayelerini dinlemek çok keyifliydi.
Listening to their stories was very enjoyable.
This usage of 'hikayelerini', while still accusative plural, specifically refers to 'childhood stories', showcasing the thematic content being shared by the author.