YOU SAID:
They have come! And their camp is very great. They must have come into the valley under the cover of dusk along both banks of the river.
INTO JAPANESE
彼らは来た!そして彼らのキャンプはとても素晴らしいです。彼らは川の両岸に沿って夕暮れの覆いの下で谷に来たに違いありません。
BACK INTO ENGLISH
They came! And their camp is so great. They must have come to the valley under the cover of dusk along both banks of the river.
INTO JAPANESE
彼らは来た!そして彼らのキャンプはとても素晴らしいです。彼らは川の両岸に沿って夕暮れの覆いの下で谷に来たに違いありません。
BACK INTO ENGLISH
They came! And their camp is so great. They must have come to the valley under the cover of dusk along both banks of the river.
That didn't even make that much sense in English.