Board Thread:Question and Answer/@comment-75.39.30.239-20150109183548/@comment-25151790-20150109222016

If Huang Long #1 is in your team or locked, it won't be highlighted.

If it's locked, you'll have to unlock it first. Tap the card and make sure the padlock icon is unlocked/blue.

If one card is in your team, you can still evolve it by dragging the card in a team into the evolution box. If both are in a team, you'll have to take one or both cards out first.

Just in case you didn't know: to get the highest stats (soldier count), make sure to max the levels of both cards and use Arcana succession when evolving them.