1 is not a valid member of Players? It's meant to return a Player?

It needs to find all the players so it can change the Properties of a PlayerGui. Here's my script:

script.Parent.MouseButton1Click:Connect(function()
    local Slot = script.Parent.Parent.Parent.Parent:GetChildren()[math.random(1,#script.Parent.Parent.Parent.Parent:GetChildren())]
    if Slot.Name == "Slot1" then
        if Slot.Visible == false then
            script.Parent.Parent.Visible = false
            local players = game.Players:GetChildren()
            for i = 1,#players do
                game.Players[i].PlayerGui.MainGui.Missions[Slot.Name].Visible = true
                game.Players[i].PlayerGui.MainGui.Missions[Slot.Name].Difficulty.Text = script.Parent.Parent.Vals.Difficulty.Value
                game.Players[i].PlayerGui.MainGui.Missions[Slot.Name].Host.Text = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent.Name
                game.Players[i].PlayerGui.MainGui.Missions[Slot.Name].Mission.Text = script.Parent.Parent.Vals.Mission.Value
                game.Players[i].PlayerGui.MainGui.Missions[Slot.Name].Players.Text = "Players: 1/4"
                game.Players[i].PlayerGui.MainGui.Missions[Slot.Name].Host.HostName.Value = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent.Name
                game.StarterGui.MainGui.Missions[Slot.Name].Visible = true
                game.StarterGui.MainGui.Missions[Slot.Name].Difficulty.Text = script.Parent.Parent.Vals.Difficulty.Value
                game.StarterGui.MainGui.Missions[Slot.Name].Host.Text = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent.Name
                game.StarterGui.MainGui.Missions[Slot.Name].Mission.Text = script.Parent.Parent.Vals.Mission.Value
                game.StarterGui.MainGui.Missions[Slot.Name].Players.Text = "Players: 1/4"
                game.StarterGui.MainGui.Missions[Slot.Name].Host.HostName.Value = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent.Name
            end
        else
            script.Parent.Text = "Error Occured! Try again!"
            wait(2)
            script.Parent.Text = "Ready!"
        end
    else
        script.Parent.Text = "Error Occured! Try again!"
        wait(2)
        script.Parent.Text = "Ready!"
    end
end)

Anything wrong with it?