El caso de la cueva secreta (Los cazamisterios 9)

When their parents aren't around, strange things always happen to Ulysses, Nora, and Bruno Misterio. Very, very strange things. Luckily, they have Bobo, a talking dog, and when he finds a clue, his nose squeaks! After their last adventure, the Misterios head to the Blue Cave to finally reunite with their parents. But when they arrive in their town, they face a new mystery… One sibling from each pair of twins has disappeared! WHAT IF IT HAS SOMETHING TO DO WITH THEIR PARENTS?