Invalid Procedure Call (Mid fxn)

Can't figure out what I'm doing wrong. Receive an Invalid Procedure Call or Argument error. Code stops at Mid function. Any help? Thanks. Receive same error when I replace ActiveCell in the Mid fxn with Range("A1")

Sub manip()

Dim strCon As String, strMod As String
Dim begin As Long, leng As Long
Dim hash As Long

Worksheets("sheet1").Activate
ActiveSheet.Range("A1").Activate

For i = 1 To ActiveSheet.UsedRange.Rows.Count Step 1

strCon = ActiveCell.Offset(i, 5).Value
begin = (InStr(1, strCon, "story:") - 7)
hash = InStr(1, strCon, " <")
Range("a1").Offset(i, 7) = begin
Range("a1").Offset(i, 8) = hash
leng = hash - begin - 7
strMod = Mid((ActiveCell.Offset(i, 5).Value), begin, leng)
Next i

End Sub