at (someone's) heels

Translations
следом за (кем-то)
The dog was always at his heels.
Собака всегда была у него на пятках.
Definitions
Following closely behind someone, often in a way that suggests eagerness or attentiveness.
Words
at

preposition
по
someone

pronoun
кто-то
is

functional word
есть
heels

noun
пятки