実家の自動車整備工場で働くはるちゃんは「笑顔で安心品質！」をモットーとする紅一点の整備士。その明るく分け隔ての無い性格から男性整備士からの信頼も厚い。しかも…同僚達の溜まった性欲を整備士としてのプロ意識と持ち前のホスピタリティを発揮して汗臭いチンポも飛びきり笑顔で抜いてくれる！！

Haru-chan, who works at her family's auto repair shop, is the only female mechanic whose motto is "Smiling and reliable quality!" Her bright and open personality has earned her the trust of the male mechanics. And what's more… she uses her professionalism as a mechanic and her natural hospitality to relieve her colleagues' pent-up sexual desires, even giving them a fantastic, smiling handjob on their sweaty cocks!