If I use Here to Help's reaction to play a Deadbloom with the discount, does the Deadbloom need to be played at the battlefield where Here to Help is hidden?

Ruling: Yes, the Deadbloom must be played at the battlefield where Here to Help is hidden. When a hidden spell or play effect causes you to play a unit, you must choose to play that unit at that battlefield.

Sequence:

• Here to Help (hidden) triggers and allows you to play Deadbloom with a discount
• Deadbloom's ability offers the option to be played to any valid location
• The hidden battlefield restriction applies, limiting the valid options
• You must play the Deadbloom at the hidden battlefield

Nuances:

• Restrictions trump allowed effects in general
• You don't control an occupied enemy battlefield, which can further limit valid play locations
• Since Deadbloom offers options for play location, those options are restricted to only the hidden battlefield