The entrance to the Secret Garden is hidden.
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means hide so the verb vocab version is to hide.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: Hide your cock (かく)! You have a ton of roosters but you don't want people to know about them, so you gotta hide your cocks. What did you think I was talking about?