Англо-русский словарь Мюллера
plunge into а) пускаться (во что-л.), начинать; Don't be too keen to plungeinto argument with him. б) ввергать; Foolish mistakes by the nation's leadershave plunged the country into a war. The city was plunged into darkness whenthe electricity supply was cut off in the storm. The news of her mother'sdeath plunged Mary into grief.
Большой англо-русский и русско-английский словарь
1) пускаться (во что-л.), начинать Don't be too keen to plunge into argument with him. ≈ Не пытайся спорить с ним.
2) ввергать The city was plunged into darkness when the electricity supply was cut off in the storm. ≈ Когда отключили электричество, город погрузился во тьму.