Mystery of Maddie Musgrove (The Time Detectives) -- Paperback / softback

When Joe Smallwood goes to stay with his Uncle Theo and cousin Maya life seems very dull until he finds a strange smartphone nestling beside a gravestone. The phone enables Joe and Maya to become time-travelling detectives and takes them on an exciting adventure back to Victorian times. Can they prove maidservant Maddie Musgrove's innocence Can they save her from the gallows