to be completely absorbed in; to fall for (something)
ゲームにのめり込んだ夏だった。
It was a summer completely absorbed in gaming.
彼は研究にのめり込んでいる。
He is completely absorbed in his research.
好奇心が強い子どもほど新しいことにのめり込む。
Children with strong curiosity tend to get absorbed in new things.