Gargoyle Hunt - Secret Supers, #3

Superheroes at college, snarky animals, living gargoyles and devious aliens living among us. Danger is the last thing on Estelle's mind when she visits the University of Oxenford for a summer course. But, mysterious thefts from the archives and shadowy figures on the ancient walls propel her into action. With Toby five thousand miles away, Estelle and her winged horse must hunt for the culprits alone.
Soon they are embroiled in a mixed bag of aliens and ancient magic. Toby's unexpected arrival throws her into turmoil and spurs events into a climax. Under pressure from his family to forge an alliance with the British clade, Toby is trapped in a web of deceit. The two supers have a week to catch the crooks and salvage his reputation.  Book 3 of the Secret Supers