Can Dennis, Gnasher and the crew catch Bea in time before Dennis's parents get home and find out she's missing? When Dennis's parents are invited to an adult-only wedding, he and Harsha devise the perfect plan to avoid nagging babysitters: they'll do it However, when Dennis's little sister Bea goes missing, they'll start to realise that babysitting isn't all it's cracked up to be Join Dennis, Gnasher, Harsha and Rubi as they chase Bea...