I am a movie director and I just received the following movie plot. Could you help me answer this question? If not, let me know by writing "Not answerable". Plot title: Young Sherlock Holmes Movie plot: Teenagers Sherlock Holmes (Nicholas Rowe) and John Watson (Alan Cox) meet and become good friends as students at London's less-than-prestigious Brompton Academy. Watson is introduced to Holmes' mentor, Rupert T. Waxflatter (Nigel Stock), a retired schoolmaster and inventor. Waxflatter's niece Elizabeth Hardy (Sophie Ward) is also Holmes' close friend and love interest. Holmes is generally recognized as brilliant but considered an undisciplined troublemaker by most of the school administration. He is closest to Professor Rathe (Anthony Higgins), his fencing instructor, who warns Holmes that he is too emotional and impulsive. Meanwhile, a hooded figure uses a blowpipe to shoot Bentley Bobster and Reverend Duncan Nesbitt with hallucinogenic thorns, causing the men to experience nightmarish hallucinations resulting in their deaths. Holmes suspects foul play but is rebuffed by Scotland Yard policeman Lestrade (Roger Ashton-Griffiths) when he suggests a connection between the deaths. Holmes is unjustly expelled from the Academy due to a rival student Dudley's machinations, having had Holmes framed for cheating. As Holmes reluctantly prepares to leave, Professor Waxflatter is shot with a hallucinogenic thorn and accidentally kills himself while trying to fend off imaginary gremlins. As Waxflatter dies he whispers the word "Eh-tar" to Holmes. Holmes secretly meets with Watson and Elizabeth and begins his investigation of the murders. Piecing together the clues a jingling-bell sound made by the killer, a piece of cloth, and the blowpipe dropped at Waxflatter's murder scene the trio uncover the existence of Rame Tep, an ancient Egyptian cult of Osiris worshippers. The cult's main weapons were blowpipes, used to shoot thorns dipped into a solution made of plant extract which causes the victim to experience realistic, nightmare-like hallucinations. They track the cult to a London warehouse where the Rame Tep are conducting human sacrifices in a secret underground wooden pyramid. After interrupting one of... My question: Who is Holmes's mentor
A:
Rupert T. Waxflatter