dark undertone

Translations
тёмный подтекст
The movie had a dark undertone that made it quite unsettling.
У фильма был тёмный подтекст, который делал его довольно тревожным.
Definitions
A subtle or hidden quality that suggests negativity, danger, or a sinister aspect, often present in art, literature, or conversation.
Words
undertone

noun
подтекст
dark

adjective
тёмный