This is the 5458th most frequent Russian word.
плену
The Russian word "плену" means "captivity" or "imprisonment."
The word 'плену' here metaphorically refers to being 'in captivity' or 'trapped' by fears.
Он оказался в плену своих собственных страхов.
He found himself a prisoner of his own fears.
Here, 'плену' is used literally to mean 'in captivity' by a foe.
Город был в плену врага несколько недель.
The city was in the enemy's captivity for several weeks.
'плену' is applied metaphorically to describe an emotional state of being captivated by love.