Christie and Agatha's Detective Agency - Book 1 - A Discovery Disappears

Book 1 in the Christie and Agatha's Detective Agency series! "Whoever gave you that sandwich did it deliberately. They wanted to sabotage Fleming's research." When Agatha accidentally eats a major scientific discovery (hidden in a sandwich!), it's a race against time for twins Agatha and Christie to find out who's trying to ruin physician Sir Alexander Fleming's reputation.