The phrase expresses about a past action. The construction verb + んじゃなかった (from no de wa nakatta ) is a common spoken Japanese pattern for “I shouldn’t have done X.”
This simple act transforms secrecy into teamwork.
『COMIC E×E』の肉アツ熱ケツ作家“みな本”が描く、人妻NTR同人シリーズが待望のコミック化!! アニメイトブックストア
: While at the event, she is pursued by her neighbor, a younger man named