Modifying data before importing

I have a field that in GatherContent that is a rich text field type and I want to map it to a plain text field in Drupal. I can see that the module doesn't let you map a rich text field to a plain text field, which I understand but I can see plenty of use cases where you might want to be able to do this.

What I'd like to do is create the mapping between the GC field and my Drupal plain text field but process it so it removes any HTML.

I can also see that Migrate API is behind the module and so could potentially use one of the process plugins to modify the data. I wondered if there any way this can be achieved?