If Vilemaw prevents a hidden Tideturner from moving back to base, can the unit that Tideturner targeted still move to its battlefield, or does the whole ability fizzle?

Ruling: The targeted unit can still move to the battlefield even if Tideturner cannot move back to base. Apply the "do as much as you can" principle and "can't beats can" - resolve all parts of the ability that are possible.

Nuances:

• The ability would only fully fizzle if moving Tideturner was a cost for moving the other unit (e.g., if the text said "move me to its location to move it to my location")
• Since it's not a cost, each part of the ability resolves independently as much as possible