Sounds like a "TV Movie of the Week" to me:

Doctors fear that the identity of a mysterious mute pianist found wandering on an English beach in April might never be known, a British newspaper reported on Monday.
...
The so-called "Piano Man", a tall blonde-haired stranger thought to be in his 20s or early 30s, was found on April 7 on the beach at Minster, on the south coast of England, soaking wet but fully dressed in a black suit and tie, with no clue as to his origin.

He has not spoken since and has not responded to written appeals while being kept under observation in the psychiatric hospital.
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When given a pencil and paper by hospital staff, he drew a grand piano -- and then, when shown a piano at the hospital chapel, he impressed his carers with a remarkable virtuoso performance.

I mean, really...