Arlo, Mrs Ogg and the Dinosaur Zoo

"4X are the most unruly, disobedient and unteachable class I have ever had to endure." Things aren't looking good for 4X. With another teacher running away screaming (literally), Arlo wonders how long the new supply teacher will survive. When Mrs Ogg takes 4X to the zoo, Arlo realises it's down to him to keep everyone in line. What Mrs Ogg fails to mention is that this is no ordinary zoo...