estaban ideando
-they/you were devising
Imperfecto progresivo para el sujeto ellos/ellas/ustedes del verbo idear.

idear

Juliet revela que ya le ha contado todo esto a Jack, pero que aún estaban ideando un plan.
Juliet reveals that she has already told Jack about it, and that they were still thinking of a plan.
Palabra del día
el mantel