Anything to do in St Malo

[Sogra]

I will have a few hours to kill in and around St Malo on Saturday, traveling south to the Morbihan region of Brittany. get off the ferry at 8.15am but cant get in the house until 4.00pm and its about 2 hours from the ferry. Any thoughts?

Thanks

[Sogra]

We are staying in a Manoir in Lignol but viewing some houses whilst we are there so may stay in various places