After his wife Ali Lee was killed by a drunk driver, Principal Ambulanceman Joe Ma has lived with his only daughter, sister (Pinky Cheung) and sister-in-law (Moon Lau). Because of his wife's death, Joe hates people who do not abide by the rules and who act recklessly. At work, Joe is strict and impartial. His new subordinate Matthew Ho is impulsive and frequently has conflicts with Joe. Meanwhile, the new Probationary Ambulance Officer Joey Law is a perfectionist and always picks on Matthew, causing the team members to feel pressured. As the intermediary, Joe works hard to maintain the team's cohesiveness and collaborative spirit. At the same time, he hopes to train a group of elite paramedics that can save more lives under different, challenging circumstances.