Board Thread:Speculation House/@comment-39854843-20190731084207/@comment-44015745-20191004035534

It's also possible that Summer isn't dead.

" Summer is believed to have died prior to the start of the series, possibly during a mission"

That's from her page, key word "believed". She never came back from her mission and was presumed dead. Salem wants Ruby alive for whatever reason, so it's possible that she wanted Summer alive for the same reason and is still holding her captive to this day.

I have an idea as to what Salem's plan might be. She wants to gather Silver-Eyed Warriors and then summon the Brothers back with the relics. Then, she'll use the hordes of Grimm at her disposal to deal with the older brother and the SEW to deal with the younger brother as revenge for her immortality, or possibly trick the younger brother with the SEW into making them fight and kill each other and humanity in the process.